Johanns was expected to announce his candidacy as early as Monday for the seat being vacated by fellow Republican Chuck Hagel after two terms. Analysts say Johanns would be the front-runner of four men seeking the GOP nomination.

Nebraska is a Republican-leaning state. Democrats have talked of recruiting Bob Kerrey, a former U.S. senator and Nebraska governor who is now a university president in New York City. Democrats control the Senate, 51-49.

As agriculture secretary, the mild-spoken Johanns pressed U.S. trading partners to remove barriers to U.S. beef, erected out of fears of mad cow disease, and to expand farm exports, which account for a quarter of farm income. He took the lead in administration proposals to deny farm subsidies to the wealthiest Americans.

In his resignation letter to Bush, Johanns said the U.S. farm sector "is stronger than ever before," with high crop prices and record farm exports.

"After careful thought and difficult deliberation, I am writing to inform you that I have decided to pursue a new opportunity to serve this great nation," wrote Johanns.

Nebraska is a major grain and cattle-producing state. Democrats in Nebraska said Johanns was leaving USDA without completing an important task -- overhaul of U.S. farm policy this year.

Johanns resigned as governor to become agriculture secretary in January 2005. Born in Iowa, Johanns practiced law in western Nebraska before election as mayor of Lincoln, the state capital, in 1991 en route to the governorship in 1998. He once said that for a former farm boy, being agriculture secretary was a dream job.

Deputy Agriculture Secretary Charles Conner was named acting secretary until Bush nominates a permanent replacement.

The Agriculture Department, with 100,000 employees, is in charge of crop subsidies, the national forests, a vast research network and public nutrition programs including school lunch and food stamps.

Ferd Hoefner of the Sustainable Agriculture Coalition, said Johanns was the first USDA chief in decades to try to rein in farm payments and to show interest in beginning farmers.

But lawmakers have faulted Johanns for the faltering campaign to create a nationwide animal-tracking system, originally embraced by the administration as a key safeguard against mad cow and other fearsome diseases. USDA relies on voluntary participation in the program.

"He has been a clear and open advocate for ethanol within the administration," said Jay Truitt of the National Cattlemen's Beef Association. Truitt said Johanns "was the first to understand" how the explosive growth of the fuel ethanol industry would squeeze livestock and meat producers.

Hicks, 32, who was convicted by a US military court of supporting terrorism, was yesterday shown mug shots of persons of interest to Australian police when they interviewed him in jail in Adelaide.

But his lawyer, David McLeod, said Hicks had largely been unable to assist them.

The hour-long interview at the Yatala maximum-security prison was the first to be conducted with Hicks on Australian soil.

Mr McLeod described it as a "sweeping up exercise" ahead of Hicks's scheduled release from jail on December 29. "He was basically asked a series of questions and shown various images," said Mr McLeod, who sat in on the questioning.

"He was unable to assist in most of it, though his intention was to assist as best he could."

Mr McLeod said Hicks had told him he would honour the US-imposed ban on speaking immediately after his release, meaning Australians would not be able to hear his account of his time with Taliban forces in Afghanistan and his treatment by the Americans until March next year at the earliest.

While the Howard Government has warned Hicks it would intervene to prevent him from profiting from the sale of his story, Mr Ruddock has acknowledged that the US gag on non-paid media interviews probably could not be enforced in Australia.

But Mr McLeod said Hicks wanted to take no chances with breaching the conditions of his plea bargain with the US military, under which he returned home in May to serve out the balance of his sentence. Under the deal, clinched in March at the controversial detention centre in Guantanamo Bay where Hicks spent most of his five years in US custody, he agreed not to speak to the media for at least a year.

More delinquencies and foreclosures can be expected in the subprime, adjustable-rate mortgage market as borrowers face interest-rate resets, Federal Reserve Chairman Ben Bernanke said Thursday.

In testimony to the House Financial Services Committee, Bernanke also said the market for those mortgages has "adjusted sharply," and that markets "do tend to self-correct."

He outlined steps the Fed is taking to help reduce the risk of foreclosure and stressed the need to beef up underwriting practices.

Just two days after the Fed lowered the federal funds rate by 50 basis points, Bernanke also said the central bank stands ready to foster price stability and sustainable economic growth.

"Recent developments in financial markets have increased the uncertainty surrounding the economic outlook," Bernanke said. "The [Federal Open Market] Committee will continue to assess the effects of these and other developments on economic prospects and will act as needed to foster price stability and sustainable economic growth," he said.

Bernanke said the recent surprise half-percentage point rate cut was designed to forestall potential effects of tighter credit conditions on the broader economy.

"We took that action to try to get out ahead of the situation," Bernanke said.

Bernanke said the central bank's economists would constantly review their internal forecast.

"There is quite a bit of uncertainty, so we're going to have to continue to monitor how the financial markets evolve and how their effects on the economy evolve and try to keep reassessing our outlook and adjusting policy to meet" the Fed's twin goals of price stability and low unemployment.

Still, he said, the global financial system is "in a relatively strong position" to work through the recent credit and market turbulence.

The two officers placed on paid leave for using a Taser on a University of Florida student explained Wednesday why they felt it necessary to use a stun gun on the unruly student.

Andrew Meyer, 21, refused to sit down at the end of a question-and-answer session with Sen. John Kerry and insisted that his questions be answered, they said.

The officers added that Meyers' rant, directed toward Kerry after the question and answer period was over, included a reference to a sex act.

Police also suggested Meyer staged the incident. They said he handed a woman next to him a camera and asked her, "are you taping this? Do you have this? You ready?"

When, police said, Meyer would not be quiet to let Kerry answer, his microphone was cut off and organizers of the event asked officers to escort him out.

"The man lifted me up and pushed Officer Wise to avoid being taken in to custody," Officer Nicole Mallo said.

When more officers were called in, they said he continued to "push, kick and elbow the officers."

When officers were only able to place one handcuff on Meyer, Sgt. Eddie King gave the order to use the Taser.

"One contact Tase to the man's left shoulder was deployed," King said.

One officer said he drew his Taser on Meyer but was ordered not to use it.

Police said it was only after his continued, active, physical resistance to being arrested that the order was given to Tase Meyer.

On his way to jail, Meyer became lighthearted, police said.

According to the police report, Meyers told officers: "I am not mad at you guys, you didn't do anything wrong, you were just trying to do your job."

Meyer's lawyer said the Taser was unnecessary and promised to vigorously fight the charges police filed, which include inciting a riot and disrupting a school function.

The videotaped incident in Gainesville, Fla., has rekindled a national debate over the controversial stun guns.

Opponents of same-sex marriage applauded Tuesday's 240-page decision, calling it a victory for traditional families and noting that most appellate courts in other states have reached similar conclusions. They also promised to mount a legislative effort of their own, vowing an aggressive push to explicitly ban same-sex nuptials in the state Constitution.

The court's majority opinion rejected the plaintiffs' claim that the 1973 statute discriminates on the basis of gender. In addition, the court concluded that while marriage is a fundamental right, it is not a right extended to gays and lesbians under current state law.

Within hours of the decision, many of the same-sex couples who had served as plaintiffs in the legal challenge gathered out side a Bolton Hill church to express anger and disappointment with the court's ruling.

Lisa Polyak and her partner of 25 years, Gita Deane, the lead plaintiffs, said they would keep fighting for legal protections for their 11- and 8-year-old daughters -- security they said would only be guaranteed through marriage.

"I feel like this decision is needlessly cruel to gay and lesbian families," said Polyak, speaking through tears during a news conference at Brown Memorial Church. "I wish these judges would have to face our children today because I have to."

David Rocah, staff attorney for the ACLU of Maryland and one of the lawyers representing the plaintiffs, said that the decision, while disappointing, did not mark the end.

"This is not the first time that the courts have not gone our way in this and other civil rights battles and it won't be the last time," he said. "I believe the march of history in this country is indeed a march toward justice."

Though the majority opinion rejected same-sex marriage, lawmakers who have for years made unsuccessful attempts at barring the unions in Maryland's Constitution said a ban was needed now more than ever.

"I assure you the constitutional marriage amendment will be reintroduced this session," said Del. Donald H. Dwyer Jr., an Anne Arundel County Republican and leading same-sex marriage opponent in the House. "Without it, there's nothing to preclude a future legal challenge made on a different argument or a different basis. The legislature ought to have the courage and the desire to publicly vote on the issue of marriage."

Since Massachusetts became the first -- and remains the only -- state to allow gays and lesbians to wed in 2003, an explosive debate over same-sex marriage has played out in courts and state capitals nationwide. Cases are pending in California and Vermont, but Maryland had been eyed as a bellwether state because of its strong liberal leanings.

Twenty-seven states have voted to ban same-sex marriage in their constitutions, while a handful -- Vermont, Connecticut, New Jersey and New Hampshire -- have adopted civil unions, which confer some of the rights of marriage.

Maryland's journey to the national spotlight began in July 2004, when 19 gays and lesbians filed a lawsuit in Baltimore Circuit Court challenging the 1973 statute. In January 2006, Baltimore Circuit Court Judge M. Brooke Murdock held that the law was unconstitutional and discriminatory. The Attorney General's Office immediately appealed the decision. Last December, the Court of Appeals heard arguments.

The bitterly divided court was passionate in its opinions, with four judges supporting the majority, two penning dissents and one concurring in part and dissenting in part.

In the majority opinion, Judge Glenn T. Harrell Jr. wrote that the state has a legitimate interest in promoting opposite-sex marriage. But he also reminded lawmakers that they have the right to consider a law permitting same-sex marriages.

"In declaring that the State's legitimate interests in fostering procreation and encouraging the traditional family structure ... our opinion should by no means be read to imply that the General Assembly may not grant and recognize for homosexual persons civil unions or the right to marry a person of the same sex," he said.

Harrell was joined by judges Dale R. Cathell, Clayton Greene Jr. and Alan M. Wilner. Judge Irma S. Raker concurred in part and dissented in part. Chief Judge Robert M. Bell and Lynne A. Battaglia wrote dissenting opinions.

The majority opinion rejected the plaintiffs' claim that denying gay marriages is a form of sex discrimination. In fact, sex discrimination does not apply to individuals, only to groups, the court stated.

"The court was unusually clear in choosing the side that sex discrimination is only from the point of view of the group," said Julie Shapiro, an associate professor at the University of Seattle School of Law. While Washington's highest court reached a similar conclusion in that state's same-sex marriage case, it did not articulate it so clearly, she said.

"The court seems to be saying that discriminating because someone is lesbian or they are gay is not as big of a problem," she said.

While the court recognized that gays and lesbians face discrimination, it also notes that as a group they are not "politically powerless," and therefore not entitled to protections.

"It is clear that homosexual persons, at least in terms of contemporary history, have been a disfavored group in both public and private spheres of our society," the decision reads. "This court nevertheless finds that a history of unequal treatment does not require that we deem suspect a classification based on sexual orientation."

"I don't think that's true," said Jana Singer, a law professor at the University of Maryland who was among the 58 professors from the University of Maryland and University of Baltimore law schools who filed friend-of-the-court briefs supporting the plaintiffs. "I think the fact that same-sex couples are excluded form the hundreds of protections of marriage indicates they are not politically powerful."

In his dissenting opinion, Bell said the majority underestimates the societal barriers facing gays and lesbians. He compared denying them the right to wed to the bans on interracial marriage, which were struck down 40 years ago in the landmark U.S. Supreme Court case Loving v. Virginia.

"To be sure, there are important differences between the African American experience and that of gay men and lesbians in this country, yet many of the arguments made in support of the antimiscegenation laws were identical to those made today in opposition to same-sex marriage," Bell wrote.

In her dissent. Battaglia said her fellow judges offer no "principled basis" for denying the plaintiffs' sex discrimination claim. "In reaching this result, the majority breathes life into the corpse of separate but equal," she wrote.

Raker, meanwhile said she fa vored decision similar to that of New Jersey's highest court, which last year required the state to extend the rights and benefits of marriage to gay couples within 180 days, but left it up to the state legislature whether to call such unions "marriage."

The court's ruling -- coming on the heels of similar conclusions reached by the high courts of many other states -- suggests that advocates of same-sex marriage are going to need to turn to legislative action, said Carl Tobias, the Williams Professor at the University of Richmond School of Law.

"The Plan explicitly does not aim at complying with the Kyoto Protocol, and therefore does not conform to the requirements of the Act," lawyers Chris Paliare and Andrew Lokan wrote in the application, filed on behalf of Ecojustice Canada and Friends of the Earth Canada.

"On its terms, the Plan provides that emissions of greenhouse gases will far exceed the levels required by the Kyoto Protocol," they said.

A Federal Court judge could theoretically respond to the application by ordering the government to file a new plan that is in keeping with the Kyoto Protocol.

"In this particular case, even though the Act is highly complicated, there are key aspects of the fudged implementation plan that does indicate a 'thumbing of the nose' against the law," University of Ottawa law professor Errol Mendes said in an interview. "If the Ecojustice lawyers can keep it simple, there is a sound basis for seeking a declaration that the government is not complying with its own Act," Prof. Mendes said.

He said the case is particularly interesting because the country may be on the verge of a succession of minority governments. "If we have legislation on more than one area passed by the combined numbers of the opposition, can the minority government just ignore the law passed by Parliament or fudge any mandate to implement it by regulation?" Prof. Mendes said.

Several legal precedents exist in which courts forced provinces or the federal government to respect its own environmental legislation, according to Albert Koehl, a lawyer for Ecojustice.

"The court is not going to be stepping into the shoes of the Minister of the Environment or the Prime Minister," Mr. Koehl said in an interview. "It would simply look at whether the plan complies with the Act."

Mr. Paliare said the case boils down to whether a government can blithely ignore its own legislation: "This case is about being accountable to the will of Parliament," he said.

Garry Keller, director of communications for federal Environment Minister John Baird, said in a statement the department would have no comment on cases before the courts.

The Conservatives have consistently maintained that years of inaction on the part of their Liberal predecessors makes it impossible to meet the targets without serious consequences for the economy.