GOP chorus: 'Decide, Ron, decide!'

Will he or won't he? If he will, when will he say so? President Reagan continues to coyly skirt the burning political question in Washington of whether he will run for a second term. Republican pressures have mounted on him to declare his candidacy - or at least signal his intentions to key leaders. While it is generally assumed the President will run again, Republicans are concerned that if Mr. Reagan bows out and does not say so soon, GOP presidential hopefuls will be scrambling frantically to make up for lost time.

The closest the President has come to saying ''yes'' is his tacit approval of the formation of a campaign reelection committee.The committee is due to open formally on Monday. Mr. Reagan will then have two weeks in which to file a statement of candidacy with the Federal Election Commission. He can, if he chooses, file with it a disclaimer stating that the committee is being authorized ''if he chooses to become a candidate.'' That would give him more time to hold off a formal announcement.

If the presidential decision is affirmative, political analysts suggest, the President will make the announcement when it can have the most public impact and capture the political environment. There is a hiatus, for instance, between the latter part of December and the time the President gives his State of the Union address in January. That period could be a politically opportune time for an announcement.

For the moment Reagan has adopted what analysts call a ''Rose Garden strategy'' of cool detachment from the political fray. While the Democrats are sparring with one another and vying for public attention, Reagan is able to act presidential - deciding major foreign policy issues, making a Cabinet change, traveling to Asia, and otherwise keeping the focus on himself as President.

Once he declares his candidacy, these observers note, he becomes an instant political target for his Democratic opponents, something he presumably wishes to defer as long as possible. He also becomes something of a lame-duck president, with less ability to influence.

''If he's sure he will run,'' comments political analyst Austin Ranney of the American Enterprise Institute, ''there are advantages to waiting, because this keeps up the interest. Some questions always have to be, 'Are you going to run?' It is good for him politically.''

There are other advantages to delaying an announcement. Candidate Reagan would have legal restrictions on his campaigning. Campaign trips would have to be paid for by the committee, not the White House. Also, the news media would be sensitive to giving him only equal time with other candidates.

In a fundamental sense, electioneering has already begun. Reagan is hard at work wooing a variety of constituencies - Hispanics, blacks, women, labor - in an effort to build a broad coalition of support. It is among these groups that the Republicans lost support in the 1982 election, and the President is using his formidable asset as a communicator to try to persuade them he is on the ''right side'' of their concerns.

''Reagan is trying to broaden his coalition,'' says political scientist James Sundquist of the Brookings Institution. ''He galvanized the Carter conservatives in 1980 and he has moved to the center later than most people. He's more ideological than most presidents, and so he's beginning to compromise.''

To Democrats, this signals that the President knows his vulnerabilities. ''Reagan wouldn't be spending so much time with blacks and so on if he didn't realize he has severe problems,'' says Michael Steed, national director of the Democratic National Committee. ''He's testing things, and that gives us a lead regarding his strategy. But it is difficult for a Democratic candidate to take shots at him.''

The President is also addressing the questions he must address if he intends to mount a serious election effort, Reagan-watchers say. He has given considerable public attention to education as a vital issue with voters. He has also sought to dispel the public image that he is anti-environmentalist by appointing a creditable official, William D. Ruckelshaus, to head the Environmental Protection Agency. His choice to replace Interior Secretary James G. Watt will also be looked on as a political message to the electorate.

Foreign policy is of concern to Reagan strategists, because opinion polls show the President losing the public's confidence in this area. Hence the vigorous effort to boost the President's image as an arms control supporter and peacemaker, as a leader prepared to exercise restraint and moderation in the global arena.

It is not unusual for an incumbent to delay making a formal announcement of his candidacy. Lyndon Johnson, weighed down by the Vietnam war, waited until February 1968 to tell a startled world he would not run. But since then the trend has been to announce fairly early. Richard Nixon made a formal announcement in January of 1972. Gerald Ford declared his candidacy in July 1975 . Jimmy Carter chose to make known his decision in early December of 1979.

It cannot be ruled out, political observers say, that Reagan is still agonizing over a decision, weighing just what a second term would entail and what it could accomplish. Some people in this town -from political professionals to street-side dilettantes - have lingering doubts that Ronald Reagan will run again. But it is still a minority view.