ANWAR SADAT was bound to be a tough act to follow as president of Egypt, but Hosni Mubarak, who has been in Washington this week, is establishing himself as his own man. It is beside the point to ask whether he could have made his predecessor's breakthrough to Israel. The test for Mr. Mubarak is whether he can adjust Egypt's policy to his own more modest personal style and, in particular, to the imminent recovery of the final territory Egypt lost to Israel in the 1967 war.

A politician is known by his enemies, and Mr. Sadat made many. This was not all bad, since a good number of his enemies, inside and outside Egypt, were made enemies by his Israel initiative. Isolation, however, was not a condition that Mr. Mubarak needed or wanted to sustain, and he has moved to accommodate many of the domestic elements--the violence-prone Moslem extremists excluded--and the foreign governments that were alienated during the Sadat period. He is taking Egypt back into a more traditional role in respect both to radical and conservative Arab regimes. With a timing obviously meant to strengthen his bargaining position in Washington, he threw out a line to Moscow, in the name of "nonalignment," before he arrived.

In short, Mr. Mubarak is holding to the new Sadat line of friendship with the United States and peace with Israel, but he is also trying to restore some of the old Nasser line of broader ties in the Arab and communist worlds. This effort comes to a focus on the issue of Egypt's approach to the Palestinian-autonomy talks now that recovery of the rest of the Sinai is only a few months away. Mr. Mubarak's evident standard for an autonomy agreement with Israel is that the agreement draw in mainline Palestinians. This alone, he evidently feels, will allow him to restore Egypt's standing with its fellow Arabs. By contrast, the Israeli government wants an agreement that excludes mainline Palestinians, whose political claims it rejects.

Mr. Mubarak is the one on the right track. Some of the words he is using in respect to the Palestinians, like "self-determination" and "national entity," are not in the Camp David texts. But the gist of what he is demanding-- Palestinian participation in a process whose outcome will be settled by mutual Arab-Israeli consent --is exactly what Menachem Begin committed Israel to at Camp David. Jimmy Carter made the same commitment for the United States. Unfortunately, Ronald Reagan has yet to make clear he accepts it.