Suddenly, Israel is very popular again. Is it because, like a neighbor, it has put in a swimming pool? Is it because it is suddenly wealthy and promises to shower gifts on its friends? The answer is none of the above. It is, instead, that there is a presidential election coming.

The latest one to swoon for Israel is Sen. John Glenn (D-Ohio). Up to now he has been on the short list of presidential candidates who have been mildly critical of the Jewish state. For instance, he favored the sale of war planes to Saudi Arabia, criticized Israel for bombing the Iraqi nuclear installation and once allegedly suggested that the U.S. should have some sort of contact with the Palestinian Liberation Organization.

These rather mild and occasional heresies earned Glenn a reputation as no friend of Israel. This is not a burden any candidate likes to take into the Democratic presidential race, and so the other day Glenn set the record straight. He lambasted the PLO and said America should not deal with it until it recognizes Israel and should, furthermore, make clear that Israel is both our ally and our friend. "Evenhandedness" when it comes to the Middle East should never be our policy, he said.Aside from his unequivocal refusal to deal with the PLO until it recognizes Israel (even though talking might someday prove useful), there is nothing terribly wrong with Glenn's statements. But there is something terribly wrong with his transparent attempt to get on the "right" side of the Israel question and to belittle American-Israeli differences--to say we are not required to agree with "every jot and tittle of Israeli policy."

The trouble is that these so-called minor differences have turned out to have profound repercussions for the United States. American marines are in Lebanon at this moment because of the Israeli invasion of last year. This is a jot and a tittle that has so far cost four American lives and will, unless Lebanon ceases to be Lebanon, cost some more.

The same can be said for the Israeli policy of establishing new West Bank settlements. To the Arabs, the settlements policy amounts to one slap in the face after another--a de facto annexation of territory seized in war. It has made the peace process that much harder.

None of this ipso facto disqualified Israel as an American friend, turning it into a rogue nation and the Arabs into paragons of national virtue. Israel remains a democracy with humanitarian values much like our own. It deserves our friendship. It deserves our support.

But even friendship and support can be modified by events. They can wax and wane depending on policy and a mutuality of interests. The goal in the Middle East is peace, not to prove our uncritical devotion to Israel--especially when it means devotion to policies many Israelis themselves abhor.As Glenn acknowledged, we have been through a cycle of pro-Israel presidential candidates having second thoughts once they win election. He vowed to break that pattern. But the pattern exists precisely because candidates like Glenn talk of Israel in glowing generalities during the campaign and then, upon election, have to deal with nasty specifics. Ronald Reagan, for instance, supported the West Bank settlements as a candidate. As president, he called for a halt to the construction of new ones.

Glenn's audience would not have hooted him down if he made these points. Indeed, some of them might have appreciated his raising the level of the debate. A recent American Jewish Committee survey, for instance, found that American Jewish leaders are sometimes much more critical of Israel than the Jewish community in general and much more willing to support a "territorial compromise" with the Arabs.

For Glenn to have articulated a position reflecting the sophistication of American Jewish leadership would have been no great sin. For him even to have continued as a basically friendly, sympathetic and informed critic of Israel would also have been no great sin. The sin is for him to patronize in the name of cause--not Middle East peace, not even the welfare of Israel, but his own election.