THE PRESIDENT, as David Broder noted in a recent column, handed the Democrats an issue when he announced his vow to bow out of Salt II.

The question is, will the Democrats accept delivery?

For the last four years, the party has been split down the middle between those who say that Democrats have to stand for something different -- like arms control -- and those who say the only hope of survival is to pass as Republicans, allies of Ronald Reagan in "peace through strength," although not without reservations.

Prof. Stanley Hoffmann of Harvard calls this philosophy "less of the same," and it has reached cult proportions since l980.

The SALT II step backwards offers the Democrats a chance to redefine themselves as a party. Will they take it?

Recent history has shown that Democrats are easily overpowered and intimidated. Let them be reminded that Reagan is the most popular American president in recorded time, let him call them "weak on defense" and they panic and flee or else get themselves invited to the White House to "negotiate" their small differences with the president.

That's what happened on the MX missile fight, in which the president's troops were led by three Democrats, who assured their colleagues that the MX was "a bargaining chip."

But not even Rep. Les Aspin (D-Wis.), who was one of the trio and in a certain light can even see "Star Wars" as a bargaining chip, has attempted to portray the cancellation of SALT II as anything but what Paul Warnke, the Carter arms negotiator promptly and rightly labelled it -- a sign that "the nuts have won" in the administration.

The Democrats will find out what they are made of in the SALT fight.

Allies of other years are scattered and disarmed. The Democrats are going to have to act out of conviction.

They have, of course, public opinion on their side. But public opinion while strongly in favor of arms control, is easily intimidated and overpowered by presidential rhetoric. And Reagan's genius for tranquilizing the masses could mean that he will get away clean on the most radical and bizarre move of his administration. All he has to say is that he will go to another summit, and apprehension will fade. He is obviously gambling that Gorbachev, zapped by Chernobyl, badly needs a summit for his own purposes.

The Democrats can't count on the Europeans this time. At the NATO foreign ministers' meeting in Nova Scotia, the diplomats bleated a bit about the unwisdom of removing all constraints from the arms race, but none of those recorded seemed to have names.

No western leader has so far publicly taken issue with Reagan.

There are two good reasons for this. One is that they are lined up at the Star Wars trough, snouts atremble at the scent of fat contracts and technological bonbons. Reagan's crazy scheme for enriching the military-industrial complex and sparing himself from the awful necessity of signing something with the Soviets has altered European politics.

The other is that the western leaders, who went to the wall with their peace movements over the European missiles, have beaten them back. In Holland, once a hotbed of antinuclear rage, voters have just reelected as their prime minister Ruud Lubbers, a champion of the missiles.

So the hope of cover from mobs of Europeans marching through the streets, and exporting indignation that will fire up the U.S. peace constituency is not there. In l982, when the freeze movement was on the rise, the Reagan administration got nervous and stopped talking about the Evil Empire. Since then, the Reagan people have learned, as they say jauntily, that "Europeans don't vote here."

The Democrats will have to take on the president because they have to. If they don't stand for arms control, what is left?

They can't look to the 22 Republican senators who are up for reelection and might have wanted to campaign on a platform of peace and prosperity, instead of scrapped arms agreement and aid to the contras. But they are, for the most part, keeping a stiff upper lip.

When asked about the effect on the November elections, Senate Majority Leader Bob Dole, who in his quest for the GOP nomination is positioning himself to the right of Jesse Helms, quipped, "A lot of people have stopped using salt."

The Democrats have to fashion Dole's joke into a make-or-break issue for themselves -- and by themselves. They have begun. Under the auspices of the House leadership, they are talking about actually biting Reagan. They are considering a bill that would stop any defense funds being used for weapons that would go over the SALT limits.

Soon now, we will find out if the Democrats have been dead since Ronald Reagan was elected, or if they were only sleeping.