Outwardly, it is a time of triumph for the White House, a time in which the president's men outdo one another in proclaiming the leadership qualities, persuasive powers and economic foresight of Ronald Reagan.

As the opening of the 1982 midterm election campaign approaches, Reagan is finally basking in the glow of good news on the economic front, potentially the economic recovery that he and those around him have long predicted. Peace seems at hand, at least temporarily, in the Middle East. Reagan's sharply defined image as a conservative partisan has been blunted by his effective use of coalition politics to achieve an unprecedented victory with Democratic assistance in the House.

"It's a tremendously important win for him," said chief of staff James A. Baker III, one of the principal architects of the victory. "It moves him into the campaign in a strong position."

Nevertheless, there are signs, as Reagan settles down on his ranch for two weeks of vacation scheduled to be interrupted only by occasional politicking, that all is not as well with the Reagan White House as it appears on the surface.

Surveys taken for Republican candidates show that Reagan has lost much of his appeal to the blue-collar voters who flocked to his banner in 1980. An undercurrent of dissension remains in the White House leadership team, though outward expressions of it are more muted now than they have been in many months. Widespread resignations and changes in the White House staff and Cabinet are anticipated after the Nov. 2 elections.

Most of all, there are nagging worries among otherwise loyal Republicans that Reagan's tax bill victory may prove to be a troubling triumph. In reaching out to embrace tax increases he had previously opposed, Reagan for the first time raised doubts about his constancy of purpose among the rank-and-file conservatives who long have provided the vital core of his support.

Speaking of these Republicans, one usually thoughtful administration aide said last week: "Emotionally, they always knew that Ronald Reagan was theirs. Now, they're not so sure." Even a White House official who is otherwise enthusiastic about the benefits that he believes Reagan's congressional victory will bring acknowledges: "A little of the glitter has been tarnished."

The problem is not with Republican conservatives alone.

On Monday the president will fly to Los Angeles to address wealthy Republicans on behalf of the Senate candidacy of Pete Wilson, the former San Diego mayor who is generally considered a GOP moderate.

Wilson, who leads his Democratic opponent, Gov. Edmund G. (Jerry) Brown Jr. in the polls, opposed the tax bill. Brown favored it. And while the president is sure to extoll Wilson to the sky and poke fun at Brown, who succeeded Reagan as governor in 1975, the irony of his position has not been lost among California politicians.

"What does Ron say on the campaign trail?" asked one veteran Republican political operative. "I'm sure he'll think of something because he always does. But it's going to be hard to urge that a Republican Congress is needed to put over the president's program when all those Democratic congressmen are waving their little thank-you notes from the president."

The reference was to the letters that Reagan, in response to a demand from House Speaker Thomas P. (Tip) O'Neill Jr. (D-Mass.), promised to write to every congressman who voted for the tax bill.

The White House responses to charges of Reagan inconsistency vary, depending on who is making them, but the overall theme is that the tax bill was a special situation and doesn't negate the many votes on which the basic administration coalition was a solid regiment of Republicans and a platoon or so of southern "Boll Weevil" Democrats.

Baker believes that this fundamental coalition will reassert itself when the Congress takes up spending measures after its late summer recess.

In fact, the coalition that the president assembled last week is not -- for Reagan -- quite as unusual or unprecedented as either supporters or opponents of the bill have maintained.

As governor of California during his first term Reagan collaborated with assembly speaker Jesse Unruh, then the most powerful Democrat in California, to push through a record tax bill with many progressive features. In his second term as governor he and Edwin Meese III -- the current White House counselor who was then Reagan's chief of staff -- responded favorably to the initiative of another Democratic speaker, Bob Moretti. Working together, they passed a far-reaching welfare bill that both tightened eligibility and increased grants for welfare recipients.

Moretti, observing that Reagan's "bark was worse than his bite," was among the first to point out that there is a notable difference between Reagan the partisan, sometimes shrilly conservative campaigner, and Reagan the pragmatic executive who is usually willing to settle for the best compromise he can get.

One White House official says that Reagan has been trying to practice coalition politics this year, too, ever since he brought together the congressional leaders of what he called "the Gang of 17" in an unsuccessful effort to work out a budget compromise earlier this year. The difference last week, the official adds, was that this was the first time the House Democratic leadership responded to the White House offer.

However, past Reagan coalition efforts in California and in Washington have alienated relatively few Republican legislators or congressmen. What is really different this time is the extent of the GOP defection, which includes 89 House members, some prominent candidates like Wilson and almost every important conservative organization in the country.

Reagan, an intuitively skilled politician, recognizes the potential danger of encouraging those who have long followed him to believe that he is straying from his central faith. In the wake of his victory he has reached out to conservatives and avoided, as one Republican says indelicately, "rubbing their noses in it." For this reason, there will be no public ceremony for the tax bill, which Reagan presumably will sign into law between horseback rides and brush clearings at his ranch northwest of Santa Barbara.

Whatever the problems with the conservatives, the White House staff leadership argues that the pluses in Reagan's victory far outweigh any minuses.

They point out that Reagan is seen as a decisive leader even by many who oppose his policies and that he reinforced this image by winning the tax bill fight. They say that he has shown he puts country above party, a quality that most Americans want in their president. Some contend that he has even helped himself on the "fairness issue" by standing up to the business community for the first time and winning.

And finally, they say, Reagan's victory has given him the ability to unite with those who opposed him as defeat would never have done.

"If he lost how could he have credibly campaigned for those who defeated the bill?" comments one White House official. "As a winner, he doesn't have to feel any restraint."

Baker puts it even more strongly, saying: "I don't see any downside to the victory at all when you compare it with the alternative, which was losing."

Ultimately, the political wisdom of Reagan's coalition course is likely to be determined outside Washington -- on Wall Street and in the economically hard-hit northeast and midwestern states whose congressional delegations overwhelmingly supported the tax bill.

The White House is openly taking credit for last week's stock market upswing and interest rate downswing -- and Reagan is certain to get the blame if the market collapses and interest rates start moving up again.

As one aide observed, "If the economy keeps going, what happened last week is going to be viewed as the triumph and turning point of the Reagan presidency."

"What if it doesn't keep going?" the aide was asked.

The official paused for a minute, shook his head, looked directly at his questioner and replied: "Then we have a lot less running room than we ever had before."