All current evidence indicates that the men running Israel are outmaneuvering the United States in purposefully implementing their blueprint for a Greater Israel in the Middle East.
As President Reagan is discovering, Israeli Prime Minister Menachem Begin, Foreign Minister Yitzhak Shamir, and Defense Minister Ariel Sharon are in no mood to be stopped. Indeed, this week's fierce assaults on west Beirut suggest it may well be too late to stop them. There is probably too much momentum now toward implementing the overall Israeli plan for any military or economic sanctions by the US to halt it in its tracks. This, despite the US call Thursday that Israel pull back its forces to the ceasefire line which existed Aug. 1 before the Israeli thrust into west Beirut.
Some of the apparent American impotence can probably be traced as far back as last September. That was when Mr. Reagan had his first meeting with Mr. Begin. As former Assistant Secretary of State Harold Saunders said on US public television this week, Mr. Reagan had an opportunity then to make clear what lines (in US eyes) Israel should not cross in pursuit of its own interests. But Mr. Reagan did not do so.
The Begin government has clearly spelled out - specifically or by implication - some of the main features of their blueprint for Greater Israel. The operations in Lebanon are merely the first step. The overall features include:
* Destruction of both the military and political power of the hard core of the Palestine Liberation Organization (PLO) in Lebanon. Every day makes this strategy plainer.
* Annexation of the West Bank and Gaza Strip - or Judea and Samaria, as the Israelis call them - so there can be no question of a Palestinian state alongside Israel on the West Bank of the Jordan. In an article in Foreign Affairs magazine, Mr. Shamir put forward his position on this subject:
''Israel has made it clear at Camp David and since that it has a claim to sovereignty over Judea, Samaria, and Gaza. In order, however, to keep a door open to a solution that will be acceptable to the parties as envisaged at Camp David, Israel has deliberately refrained from exercising its rights under this claim.''
* Insistence that the groundwork for a Palestinian state already exists on the east bank of the Jordan in the present Kingdom of Jordan. According to Yuval Neeman, leader of the Tehiya Party with a seat in Mr. Begin's Cabinet, quoted in the Aug. 1 Observer:
''This (Lebanon) war is in two parts: One is what is happening up there in Lebanon, and the other is to create a situation in which there would be practically nowhere, no place left, to create a Palestinian state other than in Jordan - where there is one already.''
He added that it was now a matter of ''working every day and every month to accelerate the Jewish colonization of Judea and Samaria and Gaza.''
Mr. Shamir, in his Foreign Affairs article, wrote: ''Reduced to its true proportions, the problem is clearly not the lack of a homeland for the Palestinian Arabs. That homeland is Transjordan or Eastern Palestine.''
Just how Syria and Lebanon can be persuaded to go along with the Begin government's version of a Greater Israel plan has yet to be explained in detail by the Israelis. Clearly it would be on Israel's terms.
As a last resort, for instance, Israel might conceivably act as midwife for a partition of Lebanon between Syria and itself. In that case, the southern part of Lebanon might become an Israeli puppet Christian state, possibly under the presidency of right-wing Christian Phalangist leader Bashir Gemayel. That would provide Israel with a buffer against both Syria and Lebanon's Muslim community. The rump might be absorbed by Syria.
When Elias Sarkis was elected President of Lebanon four years ago, it was under the protection of Syrian guns. If his successor is chosen as scheduled next month - possibly Mr. Gemayel - it will be under Israeli guns.
When the Israelis invaded Lebanon in early June, it soon became clear that they were set on doing much more than their initially proclaimed aim - clearing the PLO out of a band of territory 25 miles deep into Lebanon. Their target was the PLO leadership in west Beirut, and they halted outside Beirut a week after having crossed the border.
In the two months since then, US special envoy Philip C. Habib has been trying to negotiate the withdrawal of the PLO hard core from Lebanon to other Arab countries. From those countries (it was hoped), the PLO would henceforward pursue a political - as opposed to a military campaign - to secure recognition of Palestinian rights.
But that would leave open the option of an eventual Palestinian state on the West Bank - which the present Israeli government seems set on blocking at any cost. So while paying apparent lip-service to a negotiated resolution of the impasse over PLO withdrawal from west Beirut, the Israelis have devised a pattern of fierce intermittent military operations - leaving some US officials in high places wondering whether the Begin government's aim is to wreck the Habib mission.
The PLO was reported Aug. 5 to have dropped two of its conditions for leaving west Beirut. It would go as soon as an international force arrived in Beirut, it said, without waiting for the force to be deployed. And it would go directly to Syria without staging first in Lebanon's Bekaa Valley. It remains to be seen how Israel reacts to these concessions.