Washington — For Walter Mondale the question in the remaining two weeks before the presidential election is whether he did well enough in Sunday's debate to attract the votes of Americans who do not like Ronald Reagan but remain uncertain about the Democratic contender.
In other words, will there be a ''return of the natives'' to the Democratic camp? Will it be sufficient to eliminate the sizable gap in the polls that continues to exist between the two candidates?
Political experts here believe Mondale still faces an uphill battle in wooing back Democratic defectors and capturing enough of the independent and undecided vote to turn the tide on Nov. 6. They make these points:
* The President did well enough to erase the doubts about his competence and age. By merely holding his own in the debate and avoiding any major gaffes, he can count on holding his appreciable edge of popular support. The President has bounced back, and Reagan supporters are not likely to shift their loyalty.
* Mondale may continue to absorb the anti-Reagan vote and narrow the lead with Mr. Reagan, especially after another performance that showed him as being knowledgeable and effective.
But Mondale had already proved this in the first debate, and the gap is still wide enough that the Democratic challenger can only wait for President Reagan to make a major mistake between now and election day.
* A huge Democratic voter turnout remains crucial to a Mondale victory.
''Mondale may be able to keep his forward momentum, and there will be some return of the natives, but I doubt it will make much difference,'' says Richard Scammon, a leading election analyst. ''For the average citizen, leadership and the economy are paramount, and it will be hard for Reagan to lose. Both (candidates) looked good in the debate, so it's an improvement for the President.''
Political observers are struck by the fact that both candidates moved toward the philosophical center. It was almost as if their roles were reversed. To demonstrate his peaceableness, the President declared that he would share any new American ''star wars'' technology with the Soviets. Mondale, to show that he is not soft on defense, derided the idea, stating that he would never share such technology, although he opposed the whole concept of a strategic defense shield based in space.
In reality, say arms experts, it is naive to think that any president would end up giving the USSR the benefit of advanced American technology if it in fact were ever developed. Such advances, they say, would have enormous spinoff value for conventional defense as well.
But because of polls showing that many voters are concerned about the Reagan arms policies, the President was under constraint to show himself a peacemaker. Mondale, for his part, had to address the conservatives within his party and also try to make out Reagan to be a menace to peace, lacking in knowledge, and not competent enough to deal with the arms race. Many observers feel he failed in the latter objective.
''Time after time Mondale raised the question of whether Reagan was smart enough and so on, but Reagan wasn't cooperative,'' says political expert William Schneider of the American Enterprise Institute (AEI). ''Reagan demonstrated that he's not Dr. Strangelove, and so probably not many minds have been changed about him.''
Some analysts are puzzled as to why Mondale did not attack more vigorously, sometimes letting Reagan off the hook without a pointed rejoinder. ''Mondale sounded good, and his answers were tighter and sharper,'' says Stephen Wayne, a presidential scholar at George Washington University. ''But it's almost as if he were not following the President's answers - as when Reagan said he 'misspoke'' about the (Central Intelligence Agency's role) in Central America. He could have taken him up on it.''
Norman Ornstein, another AEI specialist, suggests that Mondale may not have set out to deliver the proverbial ''knockout blow'' but simply to burnish his own image as someone who is strong and tough. ''Mondale may have decided that it was too risky to try to fluster Reagan or attack him,'' Dr. Ornstein says. ''With only 21/2 weeks left, he may have thought it safer to position himself in the middle, rely on the commercial ads in the campaign to work their will, and hope he can energize people to get a big turnout.''
On balance, the debates in 1984 are seen to produce less payoff for the Democratic challenger than did the debate between President Carter and challenger Reagan in 1980. The reason is that four years ago the incumbent's approval rating was in the low 30s, and when voters became convinced they could support Reagan, they shifted their vote. Today the incumbent's approval ratings are so much higher that even if Mondale picks up the anti-Reagan vote, that does not appear large enough to give him the election.
''In the end the election is a referendum on Reagan as the incumbent,'' says Mr. Schneider, ''and Reagan still has 55 percent popularity.''
But while the debate may not turn things around for Mondale, analysts say, it could help the Democratic congressional and Senate races.