PITTSBURGH — It seems so quiet around here, and a bit lonely, too. They’re gone. Vanished. No signs in the streets, no ads on television. No irritating automatic phone calls. The whole political road show has moved on, to Indiana and North Carolina and parts beyond. To places where nobody knows your bowling score.

But before we here in Pennsylvania move on — the forsythia are in bloom, and we hardly noticed until Wednesday morning — it would be well to pause for just a moment to reflect on what we saw, what we’ve learned, and what we’ve yet to discover.

What we saw was quite remarkable. A state that had seldom had the undivided attention of the political world was its epicenter for well more than a month. There was one day about two weeks ago when none of the candidates was around, and people here felt slighted. Some were downright offended. That was a reflection of an entirely new and quite healthy attitude in these precincts: Politicians work for us. They’re our servants.

But that’s only half of it. It’s impossible not to conclude that a country that offers three remarkable people for president — one a black man with the ability to inspire millions, one a white woman with a mind so capacious that there is hardly a topic she cannot address with ease and depth, the third a white man with a combination of military heroism and iconoclasm unmatched by any American politician since Andrew Jackson — cannot be as politically impoverished as we might have thought a year ago.

We’ve learned, too, that people who have been forgotten politically will snap into action if they get a little attention. Pennsylvania voter rolls swelled by about 8% in the period leading to Tuesday’s voting, and turnout was more than double the figure in 2004.

The historian Major Wilson wrote that William Henry Harrison’s Whig presidential campaign had “reason as well as rhymes” — and today’s Democratic presidential nomination fight has both, in surfeit.

As a result, turnout in 1840 reached beyond 80%, a staggering increase over the 57.2% who voted in the election that took Martin Van Buren to power in 1836. The 2008 election has all the earmarks of a repeat of 1840.

But we’ve discovered that all this interest, all this passion, has a cost, at least to the Democrats.

For all the attention paid to polls in the last six weeks, the most remarkable, and most overlooked, almost certainly was the Washington Post/ABC News survey taken April 10-13 among 1,197 adults. It showed that the Democratic combat had reduced the percentage of Americans who regarded Mrs. Clinton favorably to 44% from 58%, and that the percentage of Americans who regarded Mr. Obama favorably dropped to 56% from 63% in a matter of three months.

The bad news for the Democrats is that people actually are listening to their candidates’ negative ads, and the big losers are their fellow Democrats, who eventually will have to run one of these battered candidates for president. Now, for what we have yet to discover, the most intriguing has to do with the question of experience.

Mrs. Clinton has a lot of it, although not as much as she says she has, and Mr. Obama has less, though again not as much as he says he has. But almost no impartial observer could plausibly argue the point that on this very limited measure, Mrs. Clinton has the advantage. The question then is whether she has a voting advantage.

Some of our least experienced recent candidates at least had executive records, some of them light (Jimmy Carter), some of them quite heavy (Ronald Reagan, Bill Clinton). Not one of them had a lick of foreign experience, no matter how many phony trade missions they cited when questioned about their worldliness in the most literal way of defining it. But they knew how to run things, or at least an executive government operation, and that is something neither Mrs. Clinton nor Mr. Obama possesses. Senator McCain doesn’t have it, either.

So the question now for the Democrats is whether the experience factor is indeed a political factor. The last very inexperienced Democratic senator to be nominated for president was of course John F. Kennedy of Massachusetts, but it is only fair to mention that Kennedy had served in the House and Senate for 14 years before running for president, about twice the time Mrs. Clinton has served.

The important thing isn’t that Kennedy ran against a man, Richard Nixon, with more experience — House, Senate, the vice presidency, signature foreign moments in the 1958 mob attack in Caracas and in the 1959 kitchen counter-attack in Moscow. The important thing is that he ran in a race to succeed a president who was not only popular but also worldly.

Dwight Eisenhower had been the supreme commander of Allied forces in Europe during World War II and of the North Atlantic Treaty Organization forces after the war. As president he faced the Suez and Lebanon crises and the U-2 embarrassment — three episodes that underlined the importance of experience in the Oval Office.

Now, Mr. Obama, ahead in delegates and the popular vote but recovering from a loss in Pennsylvania and still not within reach of the nomination, is facing fresh questions about his experience. But the context is far different — and the perils for the leading Democratic candidate far greater.

It is the tragedy and irony of Mrs. Clinton that the year she decided to run for president her campaign was ambushed by the unforeseen rise of a luminous, charismatic candidate.

It may be the tragedy and irony of Mr. Obama that the year he reached for the far horizon came in the very period when Americans, wondering whether President Bush lacked the experience to succeed in the White House, again make experience the measure of a presidential contender.