Jerusalem — The Israeli Knesset (parliament) Wednesday endorsed the government's conduct of the war in Lebanon by a vote of 50-40 after adebate whose outlines are likely to echo over the Israeli political landscape in coming months.
Defense Minister Ariel Sharon reflected Israeli government pique that the strategic and diplomatic triumph it believes it handed the United States was met by US peace proposals that provide an opening for a Palestinian state.
''With all our gratitude to the US Marines . . . for directing traffic'' while the PLO left, Mr. Sharon said, ''it was the people of Israel who got the PLO out.'' If President Reagan gave special US envoy Phillip C. Habib a ''Medal of Liberty'' for his negotiating achievements, then the ''Israeli people deserve the Statue of Liberty.''
The subsequent debate over the Reagan peace proposals - which the opposition Labor Party has labeled as ''positive'' and a ''basis for discussion'' - reflected Labor's intention to use them as a political rallying point despite the government implication that such support is traitorous.
Polls show that Prime Minister Menachem Begin's popularity rating has risen during the war in Lebanon and that his party would win an absolute majority if parliamentary elections were held now. But the Labor Party's position of territorial compromise with Jordan in return for peace - implicitly reflected in the Reagan proposals - seems to attract greater support from the public than does its sanction-ridden party.
Mr. Begin announced Wednesday he will call a general election next May or June - two years earlier than scheduled.
The percentage of Israelis willing to cede West Bank land in return for a peace treaty with Jordan has grown since the war in Lebanon.