Washington ? As I left this global symbol of America and its promise — ironically against a backdrop of overcast skies and terrestrial political storms — I wondered about the fate of the nation after a brutal election season.

And I thought long and hard about a question that was raised during more than one discussion: Can we truly hope to succeed in a war against the terrorists who challenge us, united in their convictions and sense of purpose, when we dither, divided and distrustful of one another?

That question occupies a key position among the most important concerns in the long, difficult battle with terrorism that lies ahead.

Hard-core global terrorists, such as the al-Qaida network, who total perhaps 150,000 and who may draw loose support from several million others, barely register as a percentage of the world’s population. And, of course, they do not represent a monolith of thought and behavior.

But what they lack in numbers, they make up for in zeal, creativity and persistence. The United States would stand a better chance of beating the terrorists back if it had held on to the unity that visited the nation ever so briefly after Sept. 11, 2001.

For a moment, Americans were as unified in their convictions and sense of purpose as the terrorists. And those miscreants — from the leaders down to the rank-and-file members — saw the collective resolve very dramatically in the United States’ launching of an overdue war against terrorism.

In Afghanistan, where Washington and its allies unleashed the first sweeping counterattack, people had grown accustomed to a lethargic America that reared its head occasionally to snap back after terrorist provocations. For a moment, the terrorists and their sponsors lost their balance, disrupted by a level of ferocity and focus that they had failed to anticipate.

But U.S. unity quickly gave way to the more familiar partisan finger-pointing and bashing, even to the point that some critics reached the stupefying conclusion that the terrorist threat shaped up as little more than a nuisance, that a war footing for the United States amounted to an overreaction.

Political campaigns this year have carried the ugliness and nastiness into other topics and to dizzying heights. America’s house appears more deeply divided than at any time in recent memory, including the Vietnam War period.

I cannot accept, however, that Americans’ core values, which range far and wide across the populace, have taken such divergent paths. My impression is that Americans, as in many cultures around the world, tend more toward moderation than to the extreme perspectives that appear to have hijacked both the Democratic Party and the Republican Party.

Americans often express surprise about the largely silent majority in other countries and cultures where extremists seize attention and influence. What about here?

My guess is that if the moderates among Democrats and Republicans, who concur far more than they differ, took an active role — perhaps by joining forces to create their own political party — they would command a powerful majority.

But that issue belongs to the future. The main challenge now is to restore America’s lost unity before al-Qaida’s next attack.

John Bersia, who won a Pulitzer Prize in editorial writing for the Orlando Sentinel in 2000, is also the special assistant to the president for global perspectives.