Arizona Sen. John McCain, fresh off Tuesday night's four-state primary sweep that secured him enough delegates to capture the Republican presidential nomination, heads to the White House today for lunch with President Bush.
He will receive an official Rose Garden endorsement from Bush, a former bitter rival of McCain's, for the nomination.
After Tuesday night's wins in Ohio, Texas, Rhode Island and Vermont, McCain now has more than the 1,191 delegates needed to be nominated this summer at the GOP convention.
"I am very pleased to note that, tonight, my friends, we have won enough delegates to claim with confidence, humility and a sense of great responsibility that I will be the Republican nominee for president of the United States," McCain said, claiming victory in front of a crowd of supporters.
McCain's win was not a surprise. McCain has been the de facto nominee since former Massachusetts Gov. Mitt Romney, his nearest rival, dropped out of the race Feb. 7 and endorsed him a week later.
On Tuesday night, McCain's sole remaining rival, former Arkansas Gov. Mike Huckabee, officially left the race.
"We started this effort with very little recognition and virtually no resources," Huckabee joked with supporters. "We ended with slightly more recognition and very few resources."
Though his nomination has long been assured, McCain has campaigned hard for the last month, as Huckabee has stayed in the race weeks after it became mathematically impossible for him to win his party's nod.
Huckabee won several key states, including Iowa and Tennessee, robbing McCain of a win on Super Tuesday. But ultimately, Huckabee did not present a serious threat to McCain.
McCain has been deferential to Huckabee, whom he says he respects and admires.
"May I say I respect Gov. Huckabee's desire to stay in this campaign," McCain said at a town hall meeting recently, in an oft-repeated refrain. "I respect that, and I will continue this campaign."
McCain's win marks the conclusion of a whirlwind primary season for the candidate, who started the 2008 presidential campaign cycle more than a year ago as the front-runner for his party's nomination, only to be counted out within months after running out of money and losing more than half his campaign staff.
For months, McCain was considered an also-ran in a crowded Republican field, not a potential winner of the party nomination.
But McCain rebuilt his campaign slowly, basing his slow but steady resurgence on town hall meetings and his ardent support for the surge of troops in Iraq.
By the end of December, McCain's campaign began to show signs of life, and his poll numbers were on the rise in the all-important state of New Hampshire, where McCain had defeated then-Gov. George W. Bush eight years earlier.
McCain went on to win the Granite State, as well as South Carolina and Florida, building a momentum that the other once-leading Republican contenders, including Romney and former New York City Mayor Rudy Giuliani, could not touch.