WASHINGTON -- What Americans saw last night was a president who is fighting -- for the limelight, for a guiding star to his presidency, for political credibility.

In his first address to the nation since the elections, President Clinton answered the Republican challenge with a ''middle class Bill of Rights'' full of presidential largesse. But even in reasserting his leadership, the president risked looking like a follower.

Candidate Bill Clinton spoke of middle-class tax breaks, shrinking government and making college more affordable. But until last month's election rout, President Bill Clinton had other priorities. Now he is presenting a program that is true to at least some of his campaign themes, but may be unsuited to the urgent political needs of his presidency.

Despite a forceful presentation, Clinton's effort to ''restore the American dream'' had less the air of a presidential initiative and more the whiff of a political response.

He is responding, of course, to the Republican ascendancy, but he is doing so on dangerous terms, inviting an engagement on a battlefield where his opponents -- true believers -- can outgun him with ease and delight.

''He can't out-tax-cut us and he can't out-tough us on defense,'' said Frank Luntz, the Republican pollster with ties to Newt Gingrich, who is in line to be the next House speaker. ''He's competing completely on our territory.''

Indeed, the House Republican leadership is urging a cut that is substantially larger than Clinton's.

The elements of the president's plan were carefully and shrewdly targeted: a college-tuition tax break to ease the greatest financial worry of many middle-class taxpayers, expanded savings opportunities for Americans under financial pressure, and tax benefits for families struggling with the cost of child-rearing.

Clinton's extraordinary holiday message, the result of weeks of agonizing in White House offices and in public, was an effort to reinject the nation's chief executive into the national debate. White House officials acknowledge privately that the president has come perilously close to becoming an afterthought, an astonishing development in a political system that from time to time prompts worry of an ''imperial presidency.''

But the danger is real enough. A Times Mirror poll this month showed that the public, by a 43-39 percent margin, thought that the Republican congressional leaders, not the president, should take the lead in solving the nation's problems. A New York Times/CBS News Poll last week said the public trusts congressional Republicans more than the president on the two principal issues of the new year: the budget and the overhaul of the welfare system. In both cases, the margin in favor of the Republicans was more than 2 to 1.

Last night's speech helped to reestablish the president's role in Washington, and his tuition plan goes to the heart of financial worries that affect millions of Americans and shape their personal and work lives.

But it may have done little to address his urgent need -- to win back Americans' confidence and to comfort them by displaying steadiness and conviction.

''He needs to command a little more affection from the American people,'' said Fred Greenstein, a Princeton specialist on the presidency. ''You have to be struck that someone who is as personable and effective personally as he has wound up being so disliked. He doesn't have to be soft and cuddly and attractive. He only has to find a consistent message and pursue it.''

Even his aides and supporters acknowledge that the president has appeared to appease conservatives, embracing proposals to make it easier to pray in public schools, restricting funding for some kinds of human embryo research and then firing Surgeon General Joycelyn Elders after her remarks about masturbation.

Now he is proposing a tax cut that Rep. Joseph Kennedy 2d, the Brighton Democrat, yesterday described as a ''short-term election bribe,'' along with generous tax treatment of retirement funds.

''He is taking elements of the Contract with America that are part of the core of being a Republican,'' said Luntz, the GOP pollster with ties to Gingrich. ''Bill Clinton is not a Republican. He is a pseudo-Republican, destroying his own base by approving our agenda. He's representing change, but . . . Republican change.''

But polls carry some sobering news for Gingrich as well. This week's Wall Street Journal/NBC News Poll says only 19 percent of the public has a positive view of the new speaker, as opposed to 32 percent with a negative view. His vow to work for a ''leaner, not a meaner government'' and to pursue ''less malice and more charity'' was an effort to take strength from what he perceives as his rivals' weaknesses.

The president sought to soften his remarks by vowing that in the next two years he would put ''country first and politics-as-usual dead last.'' That was both a return to his campaign themes and a signal that the president was determined not to cede the reformers' mantle.

White House officials contend that the president has returned to his roots as an advocate for the middle class. At the heart of their calculations is the hope that the administration and the Congress might actually find common ground.

That might yet be a formula for success. ''There's a lot of anger in the country, but there is also a great concern for results,'' said James David Barber, a Duke University specialist on the presidency. ''People want things to happen. If this can help make things happen, it might help him.''