Four years ago George W. Bush used to call him "the shadow" and promised a fresh start by pledging to "uphold the honor and dignity" of the presidency. He even joked to late-night TV's David Letterman that one of his top 10 priorities in the White House would be to give the Oval Office "one heck of a scrubbing."

But when President Bush welcomed Bill Clinton into that same office last week, those barbs were ancient history. After Clinton remarked how much he liked the new Oval Office rug, Bush encouraged him to praise his interior designer--Laura. (He did.) Over lunch with the president's father, the compliments flowed the other way. When Bush 41 inquired whether Chelsea Clinton had marriage plans, Bush 43 declared how impressed he was with the former president's daughter.

For two men at opposite ends of the political spectrum, the relationship between the 43rd and 42nd presidents has grown surprisingly warm and personal over the last six months. Clinton endorsed Bush's approach to the tsunami catastrophe, defending him against criticism about his initial response as well as raising cash alongside the president's father. Friends and aides say the two men enjoy each other's company and, as fellow pros, respect each other's political talents.

The rapid thaw started with the unveiling of Clinton's official portrait in the White House in June, when Bush told his speechwriters he wanted to deliver something "very praiseworthy, warm, funny and short." During Clinton's recent health crisis, Bush called twice to share what one of the former president's aides called "good, funny conversations." And in November, at the opening of Clinton's presidential library in Little Rock, Ark., both the president and his father delivered praise that Clinton reveled in. Clinton even pulled aside Karl Rove, the architect of Bush's election success, to congratulate him.

While aides on both sides say there's still a political chasm between the two presidents, they also point to a common style: both are Southern politicians who love to woo crowds, and whose qualities were underestimated by Washington's establishment. There's also Bush's future membership in one of the smallest elites on the planet: the ex-presidents' club. "And they're members of an even more exclusive club--the two-termers," noted one senior administration official. "To go back to the people for affirmation and be there for eight years puts them in a different class." Bush's aides said the president is already thinking of his own presidential- library plans as well as his own role after 2008, as another relatively young ex-president.

Just don't expect the working partnership to extend to Hillary Clinton, whose supporters want her to run in four years. "Honestly, I don't think getting together with George Bush is what she needs," said one ex-Clinton aide. Friendships may blossom between ex-presidents, but presidential hopefuls live in a far more hostile world.