The cliche of the season is that George W. Bush is not on Tuesday’s ballot, and one of the reasons that statement is a cliche is that it is true, at least literally. But do not doubt for a minute that of the 300 million people now residing in the United States, no single person will be affected as much by the results as the president himself.

If the polls are right and the Democrats take the House (and especially so if they take the Senate AND the House), the Bush presidency will be changed, its tone modified, its strategies transformed, its prospects altered, its legacy adjusted. Inevitably the loss of the House after a dozen years under Newt Gingrich and Dennis J. Hastert will be characterized as a repudiation of the president, but that is almost incidental. What is more important, more enduring, is how the changed landscape will change the president himself.

Change won’t be subtle

The adjustments won’t be small, the implications won’t be subtle. If you doubt me, consult Bill Clinton. He suffered a midterm massacre and found his own horizons altered (and his calendar filled with subpoena requests and grand-jury testimony and horribly uncomfortable conversations with his wife, the woman who is now running for president).

How will the Bush presidency change? Let me count the ways:

1) Quacks like a duck. Presidents in their sixth and seventh year are by definition lame ducks, but for Mr. Bush the most dreaded status in the White House will begin earlier than it might otherwise. Indeed, the president, with fewer sure allies (and fewer fail-safes) on Capitol Hill, will see his power seep away faster in early 2007 than he would have seen it slip away otherwise in 2008.

2) The distraction factor. Being president is hard enough, but when members of your administration spend their mornings testifying in front of angry opposition committee chairmen and spend their afternoons fielding subpoenas from subcommittees, it’s hard to keep your eye on the prize. Success suddenly is measured by survival, not achievement.

Wielding the veto

3) The veto pen becomes the mightiest sword. President Bush vetoed only one piece of legislation in his first six years, a remarkable figure except when you consider that the Republican House and the Republican Senate were not likely to send him bills that he would find odious enough to kill. That’s over now. House-Senate conferences will become more contentious, and the president will win fewer inside battles, with the result that a lot of legislation that was sent down Pennsylvania Avenue very soon will be sent right back up the avenue. That’s democracy in action, but it isn’t efficiency in action.

4) Agenda agonistes. Some of the priorities the president might have hoped to have achieved now have gone from “possible” on his yellow legal pad to “unlikely.” Among these are any adjustments to the Social Security system, which were in mortal danger but by Tuesday will have a stake thrust through their hearts, and further changes to the immigration system. They are deader than George Allen’s White House aspirations. No wonder President Clinton chose teenie-weenie proposals for the end of his term.

Capitol rhythms

5) Changes in the rhythms of Washington. The customary way the capital works is summed up in the old chestnut holding that the president proposes and Congress disposes. Not if the Democrats regain one or both of the chambers Tuesday. The president’s proposals will have few ears, and, to mix a metaphor, the whip hand in Washington will pass to the Democrats.

6) Lesions in the legacy. This is the time in a presidency when the chief executive tries to stitch his name in history. President Bush will have to do so without congressional assistance. This is more significant than it looks on the surface; for the president to make a lasting impact on history in these final two years, he will have to emphasize his powers as commander in chief and his prerogative to issue executive orders. That alters the way he does business, and it determines the playing field – that is, mostly foreign affairs – on which his final years are conducted. Which is ironic, given that the principal issue in the 2006 elections has been Iraq.

7) Next year isn’t 2007, it’s 2008. Not really. But when the president’s party is shellacked two years before the next presidential election, his allies are quicker than they otherwise would be to look to the future and to regard him as a figure of the past. The first beneficiary will be Sen. John S. McCain, the Arizona Republican already running hard for president. Two others might be former Mayor Rudolph Giuliani of New York and Gov. Mitt Romney of Massachusetts, who leaves office in less than two months.

For the Democrats

Now a caveat. If the Democrats do sweep into control of the House, it won’t mean the Democrats themselves are united against a fractured Republican coalition. Far from it.

The Democrats who flooded into Washington after Watergate 22 years ago, like the Republicans who surged into power under Mr. Gingrich a dozen years ago, were zealots for reform, the former mobilized to overhaul the way campaigns are run, the latter to overhaul the way the House was run. Not this time. While many of the new Democrats elected in 1974 were more liberal than the Democratic caucus they joined, and while many of the new Republicans elected in 1994 were more conservative than the GOP caucus they joined, the new Democrats of 2006 will almost certainly be less liberal than the rest of the Democrats on Capitol Hill.

That’s no consolation to the president, who is in for a very hard time. But the president isn’t the only one who will find that the old days are gone. So, they will be surprised to find, will the Democrats who may be taking power on Jan. 3, 2007. The old days are gone for them, too.