In 2004, Joe Lieberman ran for the presidential nomination of a party that no longer exists -- the hawkish Democrats -- and exited from the race after receiving a threadbare 9 percent of the vote in the New Hampshire primary. Along the way, the Connecticut senator frequently touted his "good friend" John McCain as his putative secretary of defense in a (please restrain giggles) Lieberman administration. Lieberman even ran a TV ad in New Hampshire boasting of all the McCain supporters in 2000 (mostly independents who can vote in either party's primary) who were now backing the candidate with Joe-mentum.

Monday morning -- first on the "Today" show and then at an early morning press conference in Hillsborough, N.H. -- Lieberman will endorse McCain for president. It is a fitting match of Iraq war supporters and longtime globetrotting colleagues on the Senate Armed Services Committee. There is also the poetic parallelism that Lieberman (who still bills himself as an "Independent Democrat") is now signing on with a candidate who is also seeking the nomination of a political party that may no longer exist -- Republicans who have not gone off the deep end on immigration, global warming, torture and religion.

Endorsements are what fill slow-news days in presidential politics, as reporters eagerly await the latest attack ad or press-conference rat-a-tat. For Lieberman, still galled by how Democratic Senate colleagues (especially his Connecticut counterpart, Chris Dodd) abandoned him after he lost the 2006 primary to Ned Lamont, the endorsement is another way of signaling that friendship means more to him than party. But, at the moment, there are no signs that Lieberman will go the next step by abandoning the Democrats completely and caucusing with Senate Republicans. (In the evenly divided Senate, that final act of renunciation would cost the Democrats their numeric majority.)

McCain, whose slow resurrection is reminiscent of John Kerry's return from the political dead about this time four years ago, has had quite a weekend with endorsements, having picked up the Sunday-morning blessings of the liberal Des Moines Register and Boston Globe. (In New Hampshire, the Union Leader, the only paper trusted by conservatives, backed McCain last week.) By adding Lieberman to the mix, McCain is running strong among his two core constituencies, the ink-stained wretches of the press and apostate senators. Lieberman's decision, which was made last week, is also an indication that McCain is again enough of a formidable contender for the nomination that he can call in chits from friends. Candidates languishing at asterisk levels in the polls rarely get favors even from their immediate families.

Ultimately, neither is there much mystery to the Lieberman-McCain alliance nor are many New Hampshire voters likely to remember the endorsement on primary day, Jan. 8. The 2000 Democratic vice-presidential nominee has been a party of one since the Iraq war began. Now Lieberman has finally found a comfortable refuge with McCain on the reasonable fringe of the Republican Party.