The U.S. Court of Appeals for the District of Columbia denied a petition by 17 states and several environmental groups asking it to order the Environmental Protection Agency to make that determination within 60 days.

Such a finding is a necessary first step to regulating carbon dioxide and other greenhouse gases from motor vehicle tailpipes and the smokestacks of refineries, power plants and factories. The Supreme Court more than a year ago ruled that the EPA has the authority to regulate greenhouse gases under the Clean Air Act, a step President Bush has repeatedly refused to take.

Instead, EPA is expected to issue a proposal in coming weeks that seeks public comment on a range of options the agency could take to control greenhouse gases under current law.

The law allows candidates to receive larger campaign contributions when their wealthy opponents spend heavily out of their own pockets.

The court said by a 5-4 vote that the law violates the First Amendment.

The law was challenged by Jack Davis, a New York Democrat who has so far spent nearly $4 million of his own money in two losing campaigns for Congress and says he will spend another $3 million this year.

Davis says the provision in 6-year-old campaign finance reforms unfairly rewards his opponents by letting them exceed campaign fundraising limits simply because Davis dipped into personal funds.

Writing for the majority, Justice Samuel Alito said that under the amendment, the vigorous exercise of the right to use personal funds to finance campaign speech produces fundraising advantages for the opponents of wealthy candidates.

Alito said that if the millionaire's amendment raised the contribution limits for all candidates, Davis's challenge to the law "would plainly fail," raising the question of whether Congress could easily fix what the Supreme Court struck down.

The amendment has come into play in relatively few races. Its most prominent beneficiary so far has been Sen. Barack Obama. He was able to attract additional contributions for his Democratic senatorial primary campaign in Illinois because an opponent spent nearly $29 million of his own money.

A co-author of the 2002 campaign finance law, Sen. Russ Feingold, D-Wis., said the Supreme Court decision has no impact on the central component of the reforms, the ban on six-figure political donations to political parties. Feingold co-authored the reforms with Sen. John McCain, the Republican presidential nominee-in-waiting.

Sen. Charles Schumer, D-N.Y., said the court had issued a "confounding decision that takes the First Amendment to an illogical, distorted extreme."

Davis lost in 2004 and 2006 to Republican Rep. Tom Reynolds, who spent more than $5 million in winning re-election two years ago, 51 percent to 49 percent.

Reynolds chose not to solicit increased contributions after Davis triggered the millionaire's amendment by putting at least $350,000 of his own money into the race. Reynolds could have received $6,900 from individual donors, triple the limit otherwise. Reynolds is retiring at the end of this term.

In a historic ruling, the US Supreme Court on Thursday declared 5 to 4 that the Second Amendment's guarantee of a right to "keep and bear arms" means that the government cannot enact an outright ban on certain commonly held weapons or otherwise prevent citizens from having a gun at home for personal protection or other lawful uses.

The landmark constitutional pronouncement came as the nation's highest court struck down a 32-year ban on private possession of handguns in Washington, D.C. The court also invalidated two other strict gun-control measures in the district that required that rifles and shotguns at all times be kept disassembled or secured with a trigger lock. The case is District of Columbia v. Heller.

"We hold that the District's ban on handgun possession in the home violates the Second Amendment, as does its prohibition against rendering any lawful firearm in the home operable for the purpose of immediate self-defense," Justice Antonin Scalia wrote in the majority opinion.

The majority justices said the District's strict gun regulations violated "the right of law-abiding responsible citizens to use arms in defense of hearth and home."

Justice Scalia's majority opinion was joined by Chief Justice John Roberts and Justices Anthony Kennedy, Clarence Thomas, and Samuel Alito.

In a dissent, Justice Stephen Breyer said the case would spawn unfortunate consequences. "The decision threatens to throw into doubt the constitutionality of gun laws throughout the United States," Justice Breyer wrote. "I can find no sound legal basis for launching the courts on so formidable and potentially dangerous a mission."

Scalia and the majority justices declined to spell out precisely the legal standard future courts should use in weighing whether someone's Second Amendment right had been infringed. But they left no doubt that it is a robust one.

"Under any standards of scrutiny that we have applied to enumerated constitutional rights, banning from the home the most preferred firearm in the nation to keep and use for protection of one's home and family, would fail constitutional muster," Scalia wrote.

While the high court struck down the Washington, D.C., regulations, it remains unclear how many other gun-control measures may now be on shaky constitutional ground. Some analysts suggest that a handgun ban in Chicago, similar to the ban in Washington, may emerge as the next constitutional battleground over gun rights.

Scalia sought to address concerns by many critics – and the dissenting justices – that such a ruling might lead to an arms race among American homeowners stocking up with machine guns, grenades, and rocket launchers.

"The right secured by the Second Amendment is not unlimited," Scalia wrote. "Nothing in our opinion should be taken to cast doubt on longstanding prohibitions on the possession of firearms by felons and the mentally ill," he said. The opinion did not undermine laws "forbidding the carrying of firearms in sensitive places such as schools and government buildings," he said.

He added that the opinion did not undercut laws imposing conditions and qualifications on the commercial sale of arms.

In a 5-4 vote, the court said the Louisiana law allowing the death penalty to be imposed in such cases violates the Constitution's ban on cruel and unusual punishment.

"The death penalty is not a proportional punishment for the rape of a child," Justice Anthony Kennedy wrote in his majority opinion. His four liberal colleagues joined him, while the four more conservative justices dissented.

There has not been an execution in the United States for a crime that did not also involve the death of the victim in 44 years.

Patrick Kennedy, 43, was sentenced to death for the rape of his 8-year-old stepdaughter in Louisiana. He is one of two people in the United States, both in Louisiana, who have been condemned to death for a rape that was not also accompanied by a killing.

The Supreme Court banned executions for rape in 1977 in a case in which the victim was an adult woman.

Forty-five states ban the death penalty for any kind of rape, and the other five states allow it for child rapists. Montana, Oklahoma, South Carolina and Texas allow executions in such cases if the defendant had previously been convicted of raping a child.

The court struggled over how to apply standards laid out in decisions barring executions for the mentally retarded and people younger than 18 when they committed murder. In those cases, the court cited trends in the states away from capital punishment.

Two claims remain against Grasso's $187.5 million compensation package from the exchange, which was challenged by Spitzer as exorbitant for a not-for-profit organization.

In the decision affirming a lower court's ruling, Chief Judge Judith Kaye says the challenges were based on the size of the compensation package. But she says state law required more evidence to void such a payment.

Grasso argued that a private interest like NYSE should be free to set its own compensation.

The Brussels-based rights organization, Equipo Nizkor, names the suspects as John Demjanjuk, a retired, 88-year-old auto worker in Ohio who is also being sought by Germany; Anton Tittjung; Josias Kumpf; and Johann Leprich.

All four face deportation from the United States but no country is willing to take them in, the group said.

The group said it is acting under Spain's principle of universal jurisdiction. This states that war crimes, crimes against humanity, terrorism, torture and other heinous offenses can be prosecuted in Spain even if they are alleged to have been committed abroad.

Spanish judges have used the principle to go after the late Chilean dictator Augusto Pinochet, al-Qaida leader Osama bin Laden and figures from Argentina's so-called "dirty war" of the 1970s and 80s, among other people.

The justices will likely hear oral arguments around the end of the year in the case of Edward Jerome Harbison, who was convicted in the 1983 beating death of an elderly woman in Chattanooga.

Federal appeals courts have taken different positions on the issue, making the case a good one for the court to resolve, the Bush administration said. The administration wants the justices to decide that federal law for indigent capital defendants does not extend taxpayer support to inmates' efforts to win clemency.

Separately, Harbison's execution is on hold after a federal judge ruled in September that Tennessee's three-drug lethal injection method amounted to cruel and unusual punishment because of the "substantial risk of unnecessary pain" to the inmate. The 6th U.S. Circuit Court of Appeals is now considering that case, following the high court's decision in April that upheld the constitutionality of lethal injection in Kentucky.

Harbison asked in 2006 to expand the responsibilities of his federal public defenders to also represent him in state clemency proceedings if he lost his court challenges.

Justice Department lawyers have argued against Harbison's request. "There is no constitutional right either to clemency itself or to counsel to pursue it," Justice Department lawyers said in the filing.