TWO TASKS faced the new secretary of state, Edmund Muskie, when he turned to the Mideast talks -- the lone big-ticket negotiation in which the United States is engaged. He had to defend the integrity of the Camp David process against assault from the European allies and to restart the Egyptian-Israeli talks on Palestinian autonomy. Both of these things he now has done with a directness that identifies him with the fate of the negotiations and that banishes any suggestion that the United States might stall until either the American or Israeli elections had passed.

In responding to the Europeans Monday, Mr. Muskie held to the high ground, making no insinuations of the sort that have rubbed Atlantic relations raw in recent months. Instead, he asked Europeans to limit themselves to new initiatives that would further rather than impede the Camp David process. For the first time in a negotiation, he observed, the tough issues regarding Israeli-Palestinian coexistence are being approached; to open up a new negotiating process would merely force the parties eventually to confront the same issues under less promising conditions. If any Europeans were waiting for a reasoned, respectable American argument against Europe's going it alone, Mr. Muskie supplied it.

Mr. Muskie added a brass-tacks approach to the Egyptian-Israeli talks on Palestinian autonomy, now set to resume in Washington late in June. He made no departures from the administration's Camp David line. Responding, however, to the Israeli government's recent announcement of a cap on settlements -- it said it plans just 10 more new ones -- the secretary said simply and sharply that to plant new settlements runs counter to the purpose of negotiations. He called on both Egypt and Israel to create a climate favorable to negotiation and he drew attention to the outstanding issues. In respect to the "most critical" of these, security, he defined an American compromise position with new public clarity. His remarks left little doubt of his readiness to push the pace of talks and to speak out forthrightly about them.

Let's be clear: few people now think Mr. Begin, with his beliefs and constituents and troubles, can lead Israel to agreement on autonomy. But whether he can or not, and whether he stays or goes, there is plenty of substantive negotiating to be done to prepare the issues for later resolution. In any event, if the talks go nowhere, the up-front Muskie style ensures that the public will know where to fix the blame. By accepting a responsibility to make Camp David work, the new secretary and the administration court a certain risk in this election year. But the larger risk would be to let the issue slide.