Politics is like a line of dominoes.

When everything works out, the pieces fall into place just so, and the progression -- from afar -- appears seamless.

In fact, it's anything but.

Take, for example, Rep. Thomas M. Davis III, a Republican from Fairfax County whose ambitions beyond the U.S. House of Representatives are well known. Davis, who was a page in the U.S. Senate as a child, would like nothing more than to join the upper legislative chamber.

But how?

One seat is filled by Republican George Allen, a former governor who is still very popular, especially in rural parts of Virginia.

The other Senate seat is occupied by Republican John W. Warner, a 78-year-old veteran who has achieved a reputation for moderation while holding on to power in conservative Washington.

That's it. Two seats -- both occupied by members of Davis's party. Until something changes, Davis is stuck in the House, where his moderate streak probably prevents him from rising to become speaker or majority leader.

Ahhh, but then there are the dominoes.

Allen is young enough to stay in the Senate for decades. But he's also ambitious. Although he is running for reelection to his Senate seat in 2006, most folks think he's also planning a bid for the presidency in 2008. Washington insiders give him a better than even shot of winning the Republican nomination against such luminaries as Florida Gov. Jeb Bush, Sen. John McCain of Arizona and former New York mayor Rudolph W. Giuliani.

If Allen were to win the presidency, his Senate seat would open and a special election would be called. Perfect for Davis: a domino falls.

If that doesn't happen, consider Warner's age. He would be 80 in his next bid for reelection and 86 by the time that term ends. If he doesn't run for reelection in 2008, that would clear the decks for Davis or another Republican.

Another domino falls.

So what does Davis do now?

What he can't do is actively campaign for seats that are occupied by, if not exactly his friends, then at least his allies and colleagues. Asked about the future, Davis was noncommittal, saying he has a lot to do as a leading member of the House.

And yet, there's more going on with Davis than meets the eye.

Consider that Davis spent Saturday evening 300 miles from his Fairfax County home, attending the Old Fiddler's Convention in Galax, Va. He and his wife, state Sen. Jeannemarie Devolites Davis (R-Fairfax), ate pulled pork, coleslaw and beans with other politicians from across the state and visited with fiddle players from across the country.

Why? Because he's plotting, just in case.

If the dominoes fall -- and Davis is betting that at least one of them might -- he wants to be in place to make a run. That requires raising money (which he's doing) and raising his profile outside Fairfax (which is harder; the announcement of his name in Galax barely registered any applause).

It also takes favors, which he's earning. He was the prime mover behind the candidacy of Prince William Board of County Supervisors Chairman Sean T. Connaughton (R), who lost a bid for lieutenant governor in June. Helping Connaughton earned Davis chits, even if it raised questions about whether Davis has much clout in the rest of Virginia.

Meanwhile, there's always another domino yet to fall -- his. If Davis should find an opening to run for the U.S. Senate and wins, his House seat would suddenly become available.

The guessing is that his wife might be interested in running for that seat. Fairfax County Board of Supervisors Chairman Gerald E. Connolly (D) might give it a shot, too.

And who knows, if Connolly wins, that would open up his job . . .

Stay tuned.

Rep. Thomas M. Davis III would like to run for the Senate but has to wait until a fellow Republican gives up one of Virginia's seats.