Aura of Oval Office -- Reagan's, while it lasts

Far more than the well-being of the United States economy is at stake in the White House showdown with the Democrats on taxes. The power of the presidency itself -- which many experts say has ebbed since the excesses of the Vietnam war and Watergate -- ranks highest among White House concerns.

The Reagan team has raced to put its economic plan in place while the flush of the administration's newness and goodwill is with it, before the traditional press of special interests, bureaucratic fog, and congressional assertiveness sets in.

Hence, President Reagan made a highly personal, direct bid for public support in his national address to cap his six-month "all or nothing" legislative drive for his budget and tax proposals. He spoke not from Capitol Hill, scene of his earlier economic addresses, but from the Oval Office, taking full advantage of the White House's special aura.

For the Democrats, the showdown tax vote July 29 has become the focus for rebuilding the party, learning the near-forgotten role of loyal opposition, disciplining members, and laying down the themes of the 1982 and 1984 elections.

Institutionally, Congress, too, has something at stake. The Constitution puts the tax- writing lead in the House of Representatives. And the House, particularly the tax-writing Ways and Means Committee, has felt crowded by the Republican-controlled Senate as well as the White House on its tax prerogative this year.

The public, before this week's presidential address and televised Democratic response, has been left rather out of the tax debate.

Unlike the earlier budget battle, this time House members will have little in the way of voter guidance when they vote on the House floor. The flurry of 11 th-hour special-interest "sweeteners" has confused cost-benefit comparisons of the rival Republican and Democratic bills that might have been made earlier.

The public has a largely generalized, rather than detailed, set of tax-cut desires. Polling sheds little strategic light for either tax version. A Republican survey in June showed half the public prefers a three-year cut and a one-third prefer a two-year cut. These results would appear to favor the Reagan plan. But they take no account of the "triggered" third year in the Democratic plan or other details. Also, the results came from those who said they approved of Reagan's plan.

An earlier Los Angeles Times poll showed opposite results -- one-third favoring "Reagan's cut" and half favoring "a smaller income tax cut that would make a smaller deficit in the federal budget." And other surveys show nearly half the public say they do not know enough about proposed federal tax cuts to have an opinion.

In recent days with the tax cut bidding for crucial votes, and the nationally televised "debate" between Mr. Reagan and a half- dozen Democratic spokesmen, the American public is being treated to major league politics, if not to major league baseball.

The risks to the President were high in taking the case to the public, after avoiding for months a chance to compromise earlier in the tax negotiations with House leaders.

If the White House loses, it can still claim the Democratic version largely embraces the Reagan plan, and the Republicans will gain more ground in a Senate-House conference.

But historians would likely judge that the Reagan juggernaut clearly lost steam barely a half year into its first term.

As it was, the President's address gave the Democrats the chance to put forth some newer, younger faces in rebuttal.

The Democrats played down the role of their more battle-worn party leaders, like House Speaker Thomas P. O'Neill Jr. of Massachusetts and Senate minority leader Robert C. Byrd of West Virginia.

The Democratic National Committee and party leaders on Capitol Hill agreed on a regional, across-the-spectrum roster to project a turnaround image. On one network, former Princeton basketball star Bill Bradley, now a New Jersey senator , represented the industrial crescent. Rep. Richard Gephardt of Missouri, an articulate young member of the Ways and Means Committee, weighed in for the Midwest. And from the crucial South, South Carolina Rep. Ken Holland, a self-described "boll weevil" conservative, told why he backed Reagan on the budget fight but opposes the President on taxes.

On another network, New York Sen. Daniel P. Moynihan, in the style of the Eastern intellectual elite, sought to hold the President responsible for the public's current social security jitters, as well as argue the public would again one day call on Democrats as the party of innovation in government's role.

Two Western congressmen spoke on cable television for the Democrats -- Rep. Thomas S. Foley of Washington and Sen. Max Baucus of Montana. On the eve of the vote, eight Democratic politicians, labor leaders, and economists were also to speak on TV.