Twice in the last week Anwar Sadat has suspended talks with Israel on establishing autonomy for West Bank Palestinians. The first time, his tactic had an evident purpose. The talks were going poorly, Mr. Sadat complained. He had to know that for his pains he would receive a prompt personal request to resume the talks from President Carter -- a request that in the event he was pleased to fulfill. His strategy is to stay on Jimmy Carter's sweet side.

The second suspension, however, seems different. It came yesterday, just hours after he'd put the phone down on Mr. Carter. The Israeli parliament, Mr. Sadat complained this time, had just passed a law making Jerusalem the country's capital. Does this sound strange to you? It is. In response to Egypt's demand to include East Jerusalem in the West Bank autonomy area, the Knesset -- almost unanimously, quite gratuitously -- passed a resolution affirming the 13-year-old law making Jerusalem the capital. The resolution had neither novelty nor force, it was strictly a political gesture. Mr. Sadat could have taken a verbal crack at it for the record. To protest by stepping out of the autonomy talks again, was a bit much.

Jimmy Carter will surely do his utmost not to let his pet diplomatic project be derailed by Anwar Sadat's off-again, on-again style -- just as he is doing his utmost to protect the negotiations from Menachem Begin's settlement policy. Both sets of tactics take a heavy toll of trust. One can understand how each Mideast leader is placating domestic militants and, at the same time, preparing to shift to the other the onus for any collapse in the talks. There are, however, limits. Egypt and Israel are close to them.

Consider that the Europeans, having abandoned responsible diplomacy for appeasement of their oil suppliers, wish to junk Camp David and move negotiations into a larger forum congenial to the PLO.The cynicism of this proposal is apparent, since the Europeans understand well that this "Geneva" approach is the prescription for deadlock. Israel will not negotiate there, and there is no way the United States can or should force Israel to.

That leaves Israel and Egypt with a special responsibility to make Camp David work, or at least to keep the process alive. Each side has room for last-minute compromise. Egypt's demands for setting up a "legislative" council and for cutting Israel entirely out of security duty exceed the spirit and letter of Camp David. Israel's current offers on land, water and other rights for the autonomy are insulting. Neither side can be expected to zip up its bag of negotiating tricks. But neither side can be allowed to avoid the painful concessions that negotiation requires. They knew it would be hard.