KANSAS CITY, Mo.  Whatever their ideological differences this election year, Americans seem able to agree on one thing: the political landscape being crisscrossed by the 2008 candidates is barely recognizable as the one traveled by George W. Bush and Al Gore a mere eight years ago.

Obviously, Sept. 11 and its aftermath have changed the country in countless and irretrievable ways. But even beyond the emergence of war and national security as pre-eminent concerns, there has been a profound reordering of domestic priorities, a darkening of the country’s mood and, in the eyes of many, a fraying of America’s very sense of itself.

While not universal, that tone pervaded dozens of interviews conducted over the last week with Americans of all political stripes in 8 of the 24 states that hold primaries or caucuses on Feb. 5, as well as with historians, elected officials, political strategists and poll takers. As the candidates fan out to New York and California and here to the heartland, they are confronting an electorate that is deeply unsettled about the United States’ place in the world and its ability to control its own destiny.

Since World War II, the assumption of American hegemony has never been much in doubt. That it now is, at least for some people, has given this campaign a sense of urgency that was not always felt in 2000, despite the dramatic outcome of that race.