"My rights are mine, and I am entitled to waive them just as is any other defendant," Chapman wrote.

His lawyers argued that his wish to waive appeals showed he was not competent. But the court ruled Thursday that "our review of the record in this case ... shows that Chapman's plea was competently, knowingly, intelligently and voluntarily made."

The Supreme Court ruling, written by Justice John D. Minton Jr., rejected the argument made by Chapman's defense attorneys that his guilty plea amounted to state-assisted suicide.

"Furthermore, the death penalty is not a disproportionately sentence for Chapman's heinous offenses," Minton wrote. "So Chapman's plea is not an impermissible 'suicide by court.'"

Chief Justice Joseph Lambert said Chapman's "volunteerism" played no part in his decision to uphold the death sentence.

"The wishes of a defendant, whether motivated by sincere remorse, desire to escape life imprisonment or to assert control should play no part in a death penalty determination," Lambert wrote in a concurring opinion.

Chapman admitted to killing 6-year-old Cody Sharon and 7-year-old Chelbi Sharon, and attacking their mother, Carolyn Marksberry, and their sister, Courtney Sharon. Chapman said he deserved to die for the Aug. 23, 2002 attack at Marksberry's home in Gallatin County.

The trial judge, Tony Frohlich, said at the time that he could find no legal reason not to grant Chapman's request.

Despite his request to be put to death, Chapman's court-appointed attorneys, Donna Boyce and Randall Wheeler, appealed the sentence. They argued before the Supreme Court that Frohlich shouldn't have gone along with Chapman's request for a death sentence, saying a defendant who seeks the death penalty is inherently incompetent. For that reason, the attorneys said, Chapman's guilty plea should be set aside and he should be treated for depression before a new plea hearing is held.

Chapman said in the affidavit that sending his case back to the trial court would invalidate his rights, as well as the rights of other inmates who choose to plead guilty.

The Supreme Court, in Thursday's ruling, reaffirmed that the death penalty is constitutional and that neither lethal injection nor electrocution are cruel and unusual punishments.

Despite the ruling, it could be years before an execution date is scheduled, said Allison Connelly, a University of Kentucky law professor. Defense attorneys still could appeal the case to the federal level, even asking the U.S. Supreme Court for review, she said.

Connelly said the state attorney general's office typically won't ask for an execution date until all appeals are exhausted.

The defense lawyers declined to comment, as did the attorney general's office.

Volunteering for a death sentence is not new. Since 1977, when Gary Mark Gilmore waived his appeals and was killed by firing squad in Utah, 124 inmates in 26 of the 38 states with a death penalty law have waived appeals and asked to die, according to the Death Penalty Information Center in Washington, D.C.

A second Kentucky Death Row inmate, Shawn Windsor, is also attempting to expedite his own execution. Windsor pleaded guilty in 2006 to killing his wife and son. He is on Kentucky's Death Row, but Chapman's case is further along in the automatic appeals process granted in death penalty cases.

The Supreme Court on Thursday also upheld the death sentences of Leif Halvorsen and Mitchell Willoughby who were convicted in 1983 of murdering three people in a Lexington apartment, and Fred Furnish who was convicted of murdering a Kenton County woman during a burglary in 1998.