In the realm of expectation it's all over in New Hampshire. Bush and Carter have been established as the solid favorites. The primary Tuesday features mainly a struggle by the others for the right to stand and fight in another state on another day.

On the Republican side, the rush to the fore by George Bush asserts itself in several ways. A University of New Hampshire poll shows Bush leading Reagan 37 to 34 percent and picking up momentum at a good clip. Other polls show much the same result.

Bush himself has developed with a vengeance the excessive caution familiar in front-runners. Once Mr. Available, he has suddenly become a scarce commodity. Bush scheduled only two appearances for the last week before the vote -- debated on Wednesday and Saturday nights.

A question about bribery in the Wednesday debate elicited what amounted to a version of "America, the Beautiful." Just after the debate, Bush sought out Reagan and complimented him on his answer to a hard question about a racial joke. "I felt the same kind of heat myself," Bush said in an evident effort to soften Reagan and thus avoid any fight to the bitter end.

Reagan's strong position is also well-established in the expectations. He is well known here. He has a strong organization, and he has been getting his message across to his people. He could win on Tuesday.

But he has not looked well on television. He handled the bribery question in a way that made it seem he favored corruption, and he has been on the defensive about the ethnic joke. So he has been losing support to Bush.

So the true test for Reagan is the size of his vote. He needs to get between 30 and 35 percent of the total to show that he has an undiluted core of strong support. In that way, he would achieve a blocking position and a chance to force a long, drawn-out, two-man race running all the way to the wire.

The third-man choice lies between Sen. Howard Baker and Rep. John Anderson of Illinois. Baker has at last found a comfortable theme -- the "recivilization of American politics." Anderson has shown himself to be marvelously lucid on the most complex subjects. Both candidates should draw votes from independents turned off by the Carter-Kennedy slugfest.

But Baker suffers from both weak organization and relatively high expectations. He needs to do better than 15 percent for a good third. Even then it is not clear how, or where, he would pull himself further forward.

Anderson could look good with 15 percent. Massachusetts and the posibility of a second there beckon. But thereafter it is not clear where he could go to launch a victorious drive. Moreover, both Anderson and Baker might suffer from a strong showing by a sleeper in New Hampshire -- the conservative Rep. Phillip Crane.

On the Democratic side Carter has lost the chance for a socko triumph that release of the hostages before the primary might have accorded him. But the freeze on the hostage issue and the strong patriotic stance he took in his last press conference have prevented any erosion of the president's strength. Three polls -- one by the Kennedy organization, one by CBS and one by the University of New Hampshire group -- show the president leading the senator by about 2-to-1.

Kennedy, in these conditions, is fighting to stay alive. He hits Carter from above and below and from right and left on foreign policy. He outpromises him on spending and on inflaiton. He is all over the state in small gatherings, and he has been active in fund-raising. Busloads of students have been coming in for the last-minute drive.

The obvious hope of the Kennedy forces is that they can prevent a solid Carter win here, and then go on to a triumph in Massachusetts. At that point, they play for the breaks. As the senator himself put it in an interview: "This race will be decided in an industrial state after the hostages are out. They will be voting on 21 percent inflation."

Self-deception, on a big scale, enters into that judgment. Still it may not be as silly as it sounds. Both Bush and Carter seem highly vulnerable. The driving force -- the force of events -- that has caused them to surge forward so recently can easily turn and cause them to sink just as rapidly.