Is there life after Ground Zero week? Can the anti-nuclear surge of the last six months turn from a popular enthusiasm of uncertain focus and durability into a disciplined purposeful political movement that will actually influence policy?

Already, to be sure, the movement has had an impact, though less evidently on policy than on the Reagan administration's public posture. The president has taken the common advice to try to identify himself with the movement's general aspirations to end the arms race--the better perhaps to fend off its specific projects, such as a nuclear freeze.

But that is hardly going to be enough for the movement's mobilized millions, whose attitude toward the government has a revealing curl.

The movement feels a dismay verging on disdain and even contempt for the official establishment, which, it believes, by its carelessness and profligacy has forfeited any honest claim to keeping nuclear affairs in its hands. But it acknowledges at least implicitly that nuclear choices are official and not private and that to affect official choices one must put pressure on the government, or take it over.

From the movement's point of view, the problem arises when it attempts to match its rage, alarm and impatience to the particular nuclear measures on the table at this moment.

One such measure is, for instance, to ratify SALT II, whose terms are being observed by both Washington and Moscow even though Reagan opposed ratification at the time and Defense Secretary Caspar Weinberger continues, oddly, to insist the treaty has "no value." Rep. Les Aspin has made what I find an unanswerable case for capturing this "bird in the hand." To many in the anti-nuclear movement, however, SALT II is trivial, an example of the unrewarding step-by-step slogging in the arms control trenches that has brought the world to the nuclear verge.

Many of them would go on to something they regard as bigger and grander, as a recapture of the issue from timid and discredited politicians--the Kennedy- Hatfield freeze. A petition campaign has just ensured a place for a freeze question on California's November ballot. Similar proposals could reach the ballots of eight states and the District of Columbia.

But even if you lean to a freeze on the merits--I don't, mainly because it would unsettlingly freeze our vulnerability to a first strike--the likelihood of its being forced down the throat of this administration is zero. A more sympathetic administration would still need years to negotiate it. It is a tippy vehicle for a movement that almost certainly has to show its supporters some successes to keep them aboard.

Leaders of the new lobby believe that the extensive church participation has institutionalized the movement and made it less vulnerable to bouts of political ill fortune. They suggest that the connection increasingly made between the arms race and economic distress assures the movement continuing important conservative support.

But the movement could yet be derailed by events on the model of Afghanistan and Iran, real crises that created a climate in which an imaginary pea of a "Soviet brigade" in Cuba--a pea nobody could find then and nobody can find now--capsized SALT II. Another international flareup could lead some in the movement to scuttle back toward an arms-first position, while others might head down the unilateral arms control road.

I can see a popular anti-nuclear movement, if it hangs together, latching on to one or more of the new substantive arms control ideas that are being thrown up now, but falling short of actually defining the government's negotiating position-- and probably just as well. It would still help keep the nuclear establishment and Reagan administration honest.

Ratification of SALT II would be a worthy project. Another could be the steps to prevent nuclear war by accident or miscalculation that have been recommended, separately, by Sens. Henry Jackson and Gary Hart. A third could be Sen. Charles Mathias' call for the "immediate" resumption of strategic arms negotiations, broken off a distant three years ago.

Meanwhile, there's politics. The movement has the organization and the fire and there's an election coming up in the fall.