When former U.S. Surgeon General Richard Carmona declared Thursday that he was running for the Senate from Arizona, it was a surprise to almost no one, except, it seems, Defense Secretary Leon E. Panetta.

Only two days earlier, Panetta had announced that Carmona would head a special panel to examine operations at the military's Dover mortuary, which has been rocked in recent days by the disclosures that it mishandled remains of troops killed in Iraq and Afghanistan. Panetta was even touting the appointment at a Pentagon press conference Thursday afternoon, more than two hours after Carmona announced his candidacy for the Senate.

"None of us will be satisfied until we have proven to the families of our fallen heroes that we have taken every step possible to protect the honor and dignity that their loved ones richly deserve,' Panetta told reporters. "Dr. Richard Carmona, who's the former surgeon general, 17th surgeon general of the United States, along with a distinguished panel, will conduct that review."

Alerted Friday morning that Carmona had jumped into the Senate race, the Pentagon hastily issued a statement announcing that he was stepping aside. "Dr. Carmona notified the Department this morning that he is stepping down from the panel. Secretary Panetta agrees with that decision, and he will name a replacement very soon," Pentagon spokesman George Little said.

It was the second time this week that the Dover scandal caught Panetta flat-footed. On Monday, he praised the Air Force for the "thoroughness" of its investigation and said he supported the demotion of two civilians at Dover and reprimanding of the officer in charge. On Thursday, he called for the Air Force to review the punishments given to three Dover officials after the Office of Special Counsel called them inadequate.

A senior Defense official said Carmona had not told them that he was planning to enter the race. But it has been widely reported for weeks that Democratic Party officials and even the White House had been urging him to run.

"Like most Arizonans, it's clear to me that Washington is broken," Carmona said in the statement announcing his candidacy.

In a statement released by his campaign Friday afternoon, Carmona said he was recusing himself from the panel "to avoid the opportunity for the appearance of partisanship with this important work."

"It is ... critical that the Dover review committee that I chaired and began assembling in August of this year moves swiftly and aggressively to review the actions of the Air Force in response to the allegations of the Dover mortuary staff. This important work deserves the full attention of the review panel, without any distractions," he said.

Michael A. Memoli contributed to this report.