President Reagan may wait until Labor Day or beyond to declare his intentions about seeking a second term, but Sen. Paul Laxalt (R-Nev.), his closest political ally in Congress, believes that anyone who cares will know the answer by July 4.

"If July 4 comes and goes and there's no signal otherwise from the White House, you can assume Reagan will run," Laxalt told this reporter last week. "The political realities will dictate it. It wouldn't be fair to the other potential horses in the field to let them wait beyond that without letting them know. They'd be at a terrible disadvantage."

Laxalt, general chairman of the Republican Party, said that he has no "secret commitment" from the president to run but that all of the conversations he has held with Reagan are "in the context of what we do, not whether we do it."

Accepting at face value Reagan's statement that he hasn't finally made up his mind, Laxalt said he is nonetheless doing exactly what he'd be doing if the president were a declared candidate. Laxalt said he is putting together a grass-roots organization "unparalleled in the history of American politics" that would provide an extra 5 percentage points or more of cushion in a reelection campaign.

After touring the country recently and talking to veteran party organizers, Laxalt returned to Washington convinced that Reagan is likely to be the first full-term president since Dwight D. Eisenhower to face no challenge within his own party.

"It's almost eerie, the lack of opposition," Laxalt said, adding that this is true on both wings of the party.

Laxalt said that direct-mail fund-raiser Richard Viguerie "cast his line in the water and found no takers on the deep right" and that Sen. Bob Packwood (R-Ore.) encountered opposition among his own supporters after an exploratory foray into New Hampshire.

"Reagan's our star," Laxalt said. "And whatever else anyone says about him, he has a damn good sense of timing. I'm convinced he'll be a candidate."

Two incidents, removed in time and place, reveal characteristics that reflect the strengths and weaknesses of Ronald Reagan.

The first occurred April 29 during a motorcade in Houston, where Reagan was en route to a Republican fund-raiser. When a motorcycle policeman was hurt after a collision, Reagan left his limousine and rushed to the policeman's side. The injured policeman said he was sorry that he had delayed the president, and Reagan responded: "You're sorry? I'm sorry." The president held the policeman's hand and talked with him while medics attended to the man.

This was reported at the time it happened. What wasn't reported was that Secret Service agents, doing their duty, tried to stop the president from leaving the limousine on the understandable grounds that the situation was dangerous. "I'm the president and I'm going out there," Reagan said, and he did.

He also picked up the policeman's revolver, which was swiftly taken from the inquisitive president. Reagan intimates say it was not the first time that he has chafed under security restrictions when there is something he believes he should do.

The other incident occurred May 4, when Reagan was meeting with a group of congressmen and former congressmen who had been early and longtime supporters of his. The president arrived at a reception to find three of his guests--Tom Hagedorn, Thomas B. Evans Jr. and John H. Rousselot--there while their companions had been delayed on Capitol Hill for the vote on the nuclear freeze resolution.

"Don't you fellows have to vote?" Reagan asked.

One of the company informed him that none of them could vote because all of them had been defeated while running for reelection last November.

In this case, as in others, Reagan's vaunted disdain for detail extended even to not knowing what had happened to three of his staunchest supporters in an election vital to his administration. And it explains why Reagan will be kept as far away from the press as possible this week at the economic summit at Williamsburg, Va., and on every other occasion when his staff can get away with it.

Don't look for many reiterations of Reagan's newly discovered "high-technology" themes in the months ahead. His political advisers have concluded that high tech turns off blue-collar workers, particularly in the steel and auto industries, who were targeted by Reagan in 1980 and would like to rally again to his banner in 1984.

"The unemployed steelworker may know he isn't ever going to work in his industry again, but he isn't ready to be lectured by the president about high tech," one presidential adviser said. "He wants to hear about hope for his industry and his country." Reaganism of the Week: Speaking to chief executive officers in the East Room last Monday, the 72-year-old president said: "We've begun retiring our Titan ICBMs because of their old age--don't think what I'm thinking."