In a matter of a few days, the Reagan administration has strengthened its ties with both Israel and Lebanon. But the United States appears no closer to a withdrawal of foreign forces from Lebanon.
The administration's hope apparently is that, barring any movement on the troop-withdrawal issue, the newly strengthened US-Israeli relationship will have the effect of deterring Syria or causing it to act more cautiously in Lebanon.
As Secretary of State George P. Shultz explained it in answer to a question on Thursday, the US would like Syria's President Hafez Assad to get the following message: ''That the relationship of Israel and the United States is a strong one. That Israel will continue to be able to look to its security. And that if he feels that a military victory over Israel is the way for him to get his way, he's going to be proven wrong.''
In the view of some US officials, Mr. Assad at one point not long ago thought in terms of completely dominating Lebanon. But, in their view, a newly reactivated Israeli interest in Lebanon - including some retaliatory air strikes - has caused the Syrian leader to be more prudent.
In a breakfast meeting with reporters, Secretary Shultz indicated that the US did have some ideas about concrete steps to further a withdrawal of both Syrian and Israeli forces from Lebanon, but he would not disclose them.
There are some hints from diplomats here that the Israelis may be considering another partial withdrawal in Lebanon. If coordinated with the Lebanese government, this might advance the process of getting both the Syrians and Israelis completely out of Lebanon.
Mr. Shultz spoke shortly before meeting with Lebanon's President Amin Gemayel. Mr. Gemayel later went to the White House for a meeting with President Reagan. Afterwards, Reagan said the US will ''stand by'' the May 17 Israel-Lebanon agreement on the withdrawal of Israeli forces from Lebanon.
In his talk with reporters, Shultz said that the current ''very tense situation in the Middle East'' has been brought about ''in considerable part by the large buildup of Soviet arms and troop presence in Syria.''