"The Times Square bomber spent very little time training in Pakistan because he was concerned by the length of time spent in the country being scrutinized by immigration officials. He didn't buy more fertilizer and explosive materials because there is monitoring of large purchases of fertilizer. And the 'See Something, Say Something' campaign caused a bystander to realize something was happening," Kayyem said.
Stephen Biddle, senior fellow for defense policy at the Council of Foreign Relations, added, "I think it takes a fairly brave lawmaker to publicly advocate spending less on counterterrorism. The easy way to go is to blame the expenditures as inefficient or wasting money. The tougher argument is to say, No, we're just doing too much. It exposes political risk if there is a successful attack."
Troops and Dollars Overseas: Is It Time for Them to Come Home?
In the weeks following 9/11, Americans were for the most part united that justice against an invisible enemy with no country or uniform needed to be served. Both Democrats and Republicans voted overwhelmingly for intervention to crush Al Qaeda and paralyze and dismantle the terrorist network that wanted to destroy the country.
Within a few years, Afghanistan was largely forgotten and support for the Iraq war, which always had less unanimous support than Afghanistan publicly but began with widespread bipartisan congressional support, dwindled after it was discovered that Iraq had not been harboring weapons of mass destruction under Saddam Hussein and that there was not a link between Hussein and al Qaeda.
During the election of 2008, says Biddle, when candidate Barack Obama promised to focus on Afghanistan, not Iraq, "people re-discovered the war after seven years" and "people didn't like what they saw.
"When Afghanistan became Obama's war and the Democratic Party owned it, which took place when the president put in place a substantial series of initiatives in waging the war which had not been the policy of George W. Bush, then a lot of Republicans started to verbalize they were uncomfortable with the war," he continued. "Republican support for the war in Afghanistan has been very soft since Obama's election."
While many Republicans remain committed to both Afghanistan and steadfast that there not be more cuts to defense spending, Sen. Jon Kyl, R-Ariz., recently threatened to quit the special deficit supercommittee if there were more cuts to defense. Biddle explained that those who weren't deeply committed had privately complained that Afghanistan was a "fool's errand." Eventually those private complaints became public. Now several freshman House members openly express concern about continued engagement in Afghanistan.
Meanwhile, on both side of the aisle, congressional leaders are echoing Schumer in calling for unity.
Senate Majority Leader Harry Reid, D-NV, also called on congress to remember the unity of those days. "There were not Democrats or Republicans, liberals or conservatives, red states or blue states. We were Americans," Reid said. "We need the bipartisanship of Washington."
In a video message, Sen. Lindsey Graham, R-SC, marked the tenth anniversary by praising the troops and encouraging congress to come together as they did after the attacks.
"Let's try to recapture that spirit of 9/11 to work together to solve the hard problems that face us: a mountain of debt, high unemployment, and the threats we face from radical Islam," said Graham. "There is nothing we can't accomplish if we work together."
ABC News' Sunlen Miller and Nancy Ramsey contributed to this report.