Supreme Court Justice Samuel Alito dealt Wednesday with his first case, a Missouri death row appeal, then pledged during a White House ceremony to fairly administer justice on the high court.

At his second swearing-in ceremony in two days, this time in the ornate East Room of the White House, Alito received hearty applause from lawmakers and fellow Supreme Court justices. He was lauded by President Bush as a man of "steady demeanor, careful judgment and complete integrity."

After being sworn by Chief Justice John Roberts, Alito said, "I don't think that anyone can become a justice of the Supreme Court of the United States without feeling a tremendous weight of responsibility and a tremendous sense of humility."

Alito's first vote was straightforward. He and other justices refused to give Missouri permission to speed up plans to execute a man who killed a teenage honor student.

More appeals were possible late Wednesday in the case of Michael Taylor, who would be Missouri's first inmate to be executed this year.

Separately, the court acting without Alito rejected Taylor's appeal that argued that Missouri's death penalty system is racist. Taylor is black and his victim was white. He filed the appeal on Tuesday, the day that Alito was confirmed by the Senate to replace Justice Sandra Day O'Connor.

"The death penalty as practiced in the state of Missouri discriminates against African-Americans such as [Taylor], such that it is a badge of slavery," the justices were told in a filing by Taylor's lawyer, John William Simon.

Taylor had won a stay until Wednesday afternoon in a lower court, and Missouri wanted the justices to lift that stay.

Taylor's legal team had pursued two legal challenges — claiming that lethal injection is cruel and unusual punishment and that his constitutional rights were violated by a system tilted against black defendants.

Kent Scheidegger, legal director of the Criminal Justice Legal Foundation, a pro-death penalty group, said Taylor had only a long-shot appeal because of federal limits on when courts can hear final pleas from death row inmates.

"The constant filing of new legal proceedings drags cases out forever and effectively negates the death penalty. That's exactly what Congress wanted to stop," he said.

Alito is expected to side with prosecutors more often than O'Connor, who has been the swing vote in capital punishment cases, Scheidegger said.

The votes came on Alito's first full day on the job. He took over the chambers used by O'Connor over the past year — and previously used by Justices Clarence Thomas, David Souter and Antonin Scalia.

Also Wednesday, Alito was given his assignment for handling emergency appeals: Arkansas, Iowa, Minnesota, Missouri, Nebraska, North Dakota and South Dakota.

In Missouri's appeal, the state argued that the stay was preventing it from preparing for Taylor's execution. The state must deal with "preserving security and order in the process, and adequately caring for victim's family, public, and other witnesses," the justices were told by Missouri Attorney General Jay Nixon.

Lower courts were still reviewing Taylor's lethal injection claim. The Supreme Court has blocked two executions in the past week, and has agreed to use one of the cases to clarify how inmates may bring last-minute challenges to the way they will be put to death.

The victim, 15-year-old Ann Harrison, was waiting for a school bus when Taylor and an accomplice kidnapped her in 1989. Taylor, speaking from his holding cell at the state prison in Bonne Terre, said Tuesday that he was high on crack cocaine at the time.

"I pled guilty, and I told the victim's family. I let them know how sorry I was," Taylor said.