Perhaps their inspiration was Punxsutawney Phil. On Tuesday, Pennsylvania voters raised the prospect of six more weeks of the Democratic Party's already long-running presidential nomination race. Hillary Clinton's solid 10-point margin over Barack Obama in Pennsylvania likely provides enough political propulsion to keep her in the running through the final primaries on June 3.

Barring unforeseen developments, Americans can expect to be witness for a while longer to a three-way presidential race -- two Democrats, one Republican -- John McCain.

In most competitions, two against one would be seen as a favorable situation by those rooting for the duo. But that's not the outlook of many nervous Democrats, in Minnesota and around the country. Their view is that the more these two intense rivals go after each other, the less able the ultimate survivor will be to unite the party and win in November.

Call us campaign junkies, but we find their concern overstated. It discounts the flip side of the argument -- that more exposure of these candidates' ideas and qualities could be a plus for the Democrats and, more importantly, for America. This presidential campaign is far from perfect, but it is revelatory.

What recent weeks have revealed isn't all flattering. The nation learned that Obama isn't always a rhetorical superhero. He occasionally sounds like an Ivy-educated social scientist rather than a candidate of the people. His comments about bitter small-town dwellers clinging to guns and religion in their politics worked against him with voters in a way that this race's previous guilt-by-association flaps about his pastor or his Chicago supporters did not. That's likely because they revealed a distance from, and a negative judgment of, a significant segment of the electorate. Obama has yet to find the words to reconnect with the people his comments disappointed. Meanwhile, Clinton's barbed attack in response underscored her reputation as a no-holds-barred political streetfighter.

That episode was worth seeing. But a long campaign should put it into perspective, as a diversion from discussion of the real work that confronts the next president. What all three candidates have to say about an economy in a downward spiral, food and fuel costs that rise as home values fall, the way to end the war in Iraq and to halt global warming is much more important than how Obama describes the voting psychology of rural Americans.

Fulsome discourse on those issues, highlighting their differences with McCain, is now in both Democrats' self-interest. Neither candidate can afford to offend the other's supporters. Obama, in the lead though lacking momentum, needs to revert to the issues that served him well in the race's early going. Clinton, whose hopes depend as much on the conversion of superdelegates as on the amassing of votes, needs to demonstrate that she can be trusted to put her party's November aspirations above her own immediate ones.

Fortunately, what's in the Democratic candidates' strategic interest in the nine remaining states is also in democracy's interest going forward. Let the campaign continue.