Republicans have lost their way when it comes to many core GOP principles and may be in jeopardy heading into the fall elections, Sen. Chuck Hagel, R-Neb. says.

Hagel, a possible presidential candidate in 2008, said Sunday that the GOP today is very different party from the one when he first voted Republican.

"First time I voted was in 1968 on top of a tank in the Mekong Delta," said Hagel, a Vietnam veteran. "I voted a straight Republican ticket. The reason I did is because I believe in the Republican philosophy of governance. It's not what it used to be. I don't think it's the same today."

Hagel asked: "Where is the fiscal responsibility of the party I joined in '68? Where is the international engagement of the party I joined — fair, free trade, individual responsibility, not building a bigger government, but building a smaller government?"

His frustration does not lead him to think Democrats offer a better alternative. But Hagel said he wants to see the GOP return to its basic beliefs.

"I think we've lost our way," Hagel said. "And I think the Republicans are going to be in some jeopardy for that and will be held accountable."

Hagel has not decided whether he will run for president in 2008. But respects his wife's reservations about being first lady — cited in a book about Hagel.

"I think it just shows the immense good judgment of my wife and how sane she is. I don't know of any spouse who would wish the job of president on their husband or wife," Hagel said on Fox News Sunday. "It's a big job. It's a tough job."