Standards appear to have changed since Jimmy Carter was just a candidate without a Rose Garden.

Back in May 1976, for instance, when there was a Republican in the White House, then-Democratic National Chairman Robert S. Strauss took what sounded like a hard line on what constituted presidential politicking.

Citing advisory rulings of the Federal Election Commission as his authority, Strauss declared that "once an individual has become a candidate for the presidency, all speeches made before substantial numbers of people are presumably for the purpose of enhancing his candidacy."

But that was when Gerald R. Ford was president.

You didn't hear Bob Strauss complaining when President Carter went to Philadelphia yesterday -- at White House expense.

Now chairman of the Carter-Mondale campaign, Strauss scoffed at suggestions that the visit qualified as political occasion.

"I think that's a very specious argument," he declared. "The question isn't, why isn't it political? Why is it political? He did the same type of thing long before there was a campaign."

Ending his self-imposed Iran-crisis isolation, the president and his entourage flew in two Marine helicopters for a foreign policy speech before the World Affairs Council of Philadelphia and a town meeting at Temple University.

White House and Carter campaign officials insisted that they have been quite persnickety about sorting out campaign-related expenditures, even to the point of making sure that the president's phone calls along that line are charged to a Carter-Mondale campaign credit card. They also pointed out that the Democratic primary in Pennsylvania is all over, although Philadelphia's television stations cover substantial portions of New Jersey where the voters have yet to speak.

"It's an official trip," said Ray Jenkins, a special assistant to the president. He said the World Affairs Council invited the president to speak "a little more than a year ago," and has been "on his calendar in a general way" ever since. "He could have gone a year ago," Jenkins observed.

As for the town meeting, Jenkins said that had been scheduled for early November, but was postponed because of the Iranian crisis. He said every effort was made to invite the same people who had been invited then. "It really is picking up from where he left off," Jenkins said.

An election commission official said he was "amazed that the White House is picking up the tab for this trip," especially since it included "direct voter contact" at the town meeting.

Strauss, however, said "we went out of our way" to pick a state where the Democratic delegation selection process had been completed. Jenkins said the president also wants to go to Iowa on an official visit, but has postponed those plans because the delegates there have not all been selected.

"Anything he does has impact on his candidacy," Strauss said, "but this trip doesn't do it. Sure, it'll be on television. Some people will like what he says and it will help him politically. But some won't like it, and that won't help him politically."

The Carter campaign chairman added that he considered Sen. Edward M. Kennedy's trip to Mexico last month -- at Senate Judiciary Committee expense -- far more questionable. It came just prior to the Texas primary where Kennedy forces were looking for Hispanic votes.

Jenkins said it is often difficult to draw the line between official and political business, but he argued that it "kind of puts any president in a Catch 22" to count any out-of-town speechmaking in an election year as a campaign expenditure.

Asked about his protest to the FEC four years ago, when he complained about the Republican National Committee's payment of some of Ford's early travel expenditures on so-called "party-building trips," Strauss said he saw no inconcistency."

"My standards are not different," he declared. "They're exactly the same."

THE FEC, however, has refined its thinking, according to spokeswoman Sharon Snyder. Since its 1975 ruling concerning speeches by declared presidential candidates, she said, the commission has issued subsequent opinions allowing various activities, including speechmaking, as nonpolitical as long as they did not include any solicitations for campaign funds or "vote-for-me" kind of talk.