At a town hall meeting in Catonsville last week, Sen. Benjamin L. Cardin spent a half-hour answering questions, including whether Congress would cut Medicare, address immigration or impeach President Barack Obama.

Despite the breadth of the discussion, the Maryland Democrat and member of the Senate Foreign Relations Committee did not hear a single question about Iraq or Afghanistan, the broader goal of curtailing terrorism or efforts to bolster security in the United States.

Ten years after the attacks of Sept. 11, 2001, stripped the nation of its sense of invulnerability and realigned politics in a way not seen since the height of the Cold War, their impact on voters, candidates and elections has waned.

As Americans look ahead to the 2012 presidential vote, the focus is once again on the economy, as in the previous two national elections in 2010 and 2008.

"In a way there's a kind of Sept. 11 hangover," said Karlyn Bowman, a senior fellow at the American Enterprise Institute, which released a report recently that summarized a decade's worth of public opinion polls on terrorism. "It's on the back burner at a very steady simmer, but it's still on the back burner."

A month after the attacks, 46 percent of Americans viewed terrorism as the nation's foremost problem, according to a Gallup poll. Five years later, the figure had slipped to 11 percent. Last year, only 1 percent saw terrorism as the top problem — about the same as before the Sept. 11 attacks.

But the attacks, which will be revisited in anniversary events across the country in the coming days, had a lasting impact on the federal government, including the creation of the Department of Homeland Security, new policies that eased restrictions on domestic surveillance and the doubling of defense spending over the past decade.

No event since the attack on Pearl Harbor on Dec. 7, 1941, has had such an effect on the nation's psyche, says American University historian Allan Lichtman.

"Pearl Harbor was really important because it broke the myth of American isolationism," said Lichtman, an unsuccessful Maryland Democratic candidate for U.S. Senate in 2006. Sept. 11 "was another paradigm shift: It broke the myth of American invulnerability."

But while the attacks orchestrated by al-Qaida played a significant role in the 2002 and 2004 elections, and continued to have an impact in 2008, their political potency has slid — in part, some say, because of public perceptions about the government's response to Sept. 11.

Despite growing distrust of Washington, nearly eight in 10 people give the government high marks for preventing terrorism, according to a Pew Research Center poll released Thursday.

"It's human nature that when you have a crisis you pay attention to it for a period of time and you try to prevent it from happening again," said Rep. Steny H. Hoyer, the Southern Maryland lawmaker who is the second-highest-ranking Democrat in the House. "Eventually, the immediacy of the danger fades."

The Republicans now crisscrossing the country in pursuit of the presidential nomination have in some cases gone out of their way to avoid discussing the threat of terrorism.

And while the patriotic bipartisanship that immediately followed the 2001 attacks led to drastic changes for the federal government, even some of those shifts in policy are starting to come undone.

Part of what drove politics after the attacks was an increased level of public confidence in government — a predictable response in the aftermath of a crisis, said Kimberly Gross, a professor of media and public affairs at George Washington University who has studied public trust.

"It's not obvious who will deal with it or who will protect people, so there's this huge leap in trust," Gross said. "It didn't last hugely long."

Politically, the attacks nudged members of both parties closer together as the Cold War-era stereotype about Democrats being soft on defense became a far more effective tool for Republicans to use in the face of a broad "war on terrorism."

A year after the Sept. 11 attacks, 29 of 50 Senate Democrats joined all but one Republican in supporting the U.S.-led invasion of Iraq.

In his 2004 re-election effort, President George W. Bush repeatedly tried to paint his Democratic opponent, Massachusetts Sen. John Kerry, as weak on defense. One television ad aired by the Bush campaign weeks before the election showed a pack of wolves lurking in a forest as the narrator chastised Kerry for voting "to slash America's intelligence operations."