THAT NOISE you hear from the White House is the sound of the ice cracking around Mr. Reagan's position in the Euromissile talks. It may not signify that an agreement with the Russians is in sight -- they will have something to say about that -- but it does mean a new stage in the negotiation is on.

In the first stage, Mr. Reagan proposed that Moscow remove all its medium-range weapons trained on Europe; in return, he would forgo matching them. At the time, most Europeans seemed to find the "zero-zero option" reasonable and desirable, but as time and peace agitation and Soviet propaganda went on, they started to wobble, thus bringing into question whether NATO's "stick" -- the threat to start deploying new missiles -- would still be in hand.

Vice President Bush, dispatched to calm them, brought back a recommendation to defer the quest for an early zero-zero agreement and to pursue instead an "interim" solution by which Soviet missiles would be lowered and American missiles deployed to the same "zero plus" on both sides. Just this sort of compromise was tentatively explored by Soviet and American negotiators last summer. President Reagan himself seems to be moving that way now.

Though zero-zero "remains the best and most moral outcome," he said Tuesday, "we are negotiating in good faith in Geneva and ours is not a take-it-or-leave it proposal." He then spelled out his criteria, noting that they are "supported by all the allies after long and careful consultation": equality of Soviet and American missile rights and limits; no counting of the 162 British and French missiles, as Moscow has proposed in order to keep its Euromissile total at the same 162 against zero for the United States; no shifting of Soviet missiles from Europe to Asia, where they could be retargeted against American friends; and "effective" verification.

In brief, Mr. Reagan is coming down off his opening position because it did not appear -- to the allies, to his critics, to some of his aides and now evidently to him -- that he could get the allies to stick with it. And without the allies, he would have nothing. He had deplored the pressures in a democracy that make presidents water down their negotiating proposals to the Kremlin, and it could not have been pleasant for him to bargain out new proposals inside the American government now. But he does appear to be regrouping around a position with two virtues: it still meets his own tests for arms control, and it has a much better chance of holding the allies to deployment if talks fall short. If this is so, people should give him a chance to negotiate.