WASHINGTON (AP) — Republican presidential nominee-in-waiting John McCain has a lunch date Wednesday with President Bush at the White House — and the promise of a Bush endorsement.

There'll be a formal welcome at the North Portico, followed by lunch in Bush's private dining room and an endorsement in the Rose Garden.

In recent weeks, Bush has gone out of his way to defend the senator's conservative credentials, saying criticism of the Arizona senator has been grossly unfair. The two were bitter rivals in 2000.

"The president has said he looks forward to vigorously campaigning for the GOP and tonight it has become clear that the GOP nominee will be Sen. John McCain," White House press secretary Dana Perino said Tuesday night. "Of course the president is going to endorse the GOP nominee, which is going to be Senator John McCain."

Bush made morning phone calls to McCain's former rivals Mike Huckabee, Mitt Romney and Fred Thompson to congratulate them on their primary campaigns. He intends to call Rudy Giuliani later.

"He said he appreciated their ability to keep their sense of humor and that he looks forward to working them in the '08 election," Perino said.

Asked about McCain's past disagreements with Bush, she said: "The point of these elections is for the candidate to run as their own person. Elections are about change and going forward, and one of the most attractive things about Senator McCain to the Republican Party is that he has been his own person. He has blazed his own trail and he will have to make the case as to why voters should vote for him."