Sen. Chuck Hagel (R-Neb.) declined to endorse his party's likely presidential nominee, Sen. John McCain of Arizona, and said he would consider serving in a Cabinet under Democrat Barack Obama.
But Hagel, who last year considered a White House run as an independent, said he would remain a registered Republican, at least for now.
"I don't have any plans to endorse any candidate," Hagel, 61, said in an interview on Bloomberg Television's "Political Capital With Al Hunt," to be broadcast today.
Hagel broke with his party over the war in Iraq, which he called a "catastrophic mistake." He voted with Democrats to withdraw troops and against President Bush's troop buildup in Iraq last year.