At Point East Condominium and all through the predominantly Jewish Gold Coast here, the Carter presidency has been divided into two periods: before the Andrew Young affair and after it.

"Before Young's meeting with the PLO, Carter's support was high," said Annie Ackerman, the president's staunchest supporter along the Gold Coast. "Now it's not so good."

As Ackerman and others made their rounds in the condominiums trying to organize cadres for the Oct. 13 strawvote caucus test against the draft-Kennedy movement, it became clear that many people believed Young's actions had been orchestrated by the Carter administration and that there was concern about the administration's committment to Israel. Finally, Ackerman called a Carter political operative with this message: "You've got to get someone down here."

It was Carter's man for all seasons, Robert S. Strauss, who answered the call.

Late Wednesday night, Strauss stood before 1,500 Point East residents, and with his voice rising to a shout, urged them to believe in the Carter administration's support for Israel.

"I've built my reputation on one thing," Strauss said, "and that is telling it as it is. Let me say to you that this nation, under this president, is committed to the proposition that there must be stability in the Middle East.

"And this president is committed to the proposition that the foundation of a stable Middle East is a safe and a strong and a sound and a secure state of Israel.

"And anybody that represents to you that the contrary is true" and here his voice took on added determination -- "is a liar or a fool or confused or a mischief-maker. Let that be clear."

Strauss, repeatedly reminding his audience that he, too, was Jewish, held back from direct criticism of Young's actions. But he urged the people there and at an earlier meeting in Fort Lauderdale to "look at the record" of the Carter administration's policies on Israel and to listen to Moshe Dayan when he describes Carter as the most supportive American president in history.

Do not, he told the audiences, be "misled by demagogues."

Strauss also told them not to be misled by the State Department. "I have had some trouble with various levels of people in the State Department, too," he said laughing. "I can tell you I won't have those problems any more." He added quickly that he was referring to a level below that of Secretary Cyrus R. Vance, though he did not elaborate.

The United States, he said, does not favor an "independent Palestinian state" despite what "you may have read or heard in recent months."

But he cautioned them that the administration had to listen to groups other than American Jews and to nations other than Isreal as it formulated Middle East policy.

"For each one of you who feels so strongly on one side of this issue, there is someone else out there who feels equally strongly on the other side."

Strauss also said in Fort Lauderdale that he was "concerned" about Israel's image in the United States because of its decisions on West Bank settlement and its military actions in Lebanon.

It was far from clear that Strauss' appearance would translate into support on Oct. 13 or in the more important March 11 Florida primary. After his speech at Point East, only 100 of the 1,500 persons signed up for buses to take them to vote for Carter at the caucuses.

But virtually everyone interviewed after his talks said they at least better understood administration policy on Israel.

And Annie Ackerman at least seemed relieved, "We really needed that," she said.