WASHINGTON — As Americans debate whether they are better off now than they were four years ago, there is a similar question with a somewhat easier answer: Are you safer now than you were when President Barack Obama took office?

By most measures, the answer is yes.

More than a decade after terrorists slammed planes into the World Trade Center in New York, the Pentagon and the Pennsylvania countryside, Americans have stopped fretting daily about a possible attack or stockpiling duct tape and water. Getting through airport security has become a routine irritation, not a grim foreboding.

While the threat of a terrorist attack has not disappeared, the combined military, intelligence, diplomatic and financial efforts to hobble al-Qaida and its affiliates have escalated over the past four years and paid off. Terrorist leaders, including Osama bin Laden, are dead and their networks in Pakistan, Yemen and Somalia disrupted.

In some cases, the Obama White House simply continued or intensified programs and policies begun by the Republican administration of President George W. Bush. But Obama pursued a more aggressive drone campaign to target terrorist leaders, broadening efforts to help at-risk nations bolster their own defenses, and put in place plans to end the war in Iraq and bring troops out of Afghanistan.

As a result, terrorism worries have taken a back seat to the nation’s economic woes.

Unlike previous elections, national security is not a big campaign issue this year.

Mitt Romney made no mention of terrorism or war during his acceptance speech at the Republican National Convention last week. Although public opposition to the war in Afghanistan has grown, it’s not a top dinner table topic for most Americans.

“I would have said four years ago that the al-Qaida movement was emerging as a bigger problem, especially with the emergence of affiliates in places like Yemen and with the spike in homegrown attacks,” said Phil Mudd, a senior counterterrorism official at the CIA and FBI during the Bush and Obama administrations. “But I would say today that al-Qaidaism is on the decline. By any balance, the number of places where people want to come after us has declined in the past four years.”

Mudd, now a senior research fellow at the nonpartisan New America Foundation, said that while militants in other countries may still be causing problems in their own areas, they are less likely to “be sitting there saying how do we get to Los Angeles, and that’s a big change.”

Still, other international dangers remain. Ongoing efforts to dissuade Iran from developing nuclear capabilities have not worked. As Israel’s worries about the nuclear threat grow, the possibility of U.S. involvement in an Israeli strike against Iran has become a front-burner issue.

Defense officials are wary of China’s military growth, and U.S. intelligence agencies have accused Beijing for stealing American high-tech data through computer-based attacks. U.S. officials and security experts are increasingly warning that the United States is highly vulnerable to cyberattacks, including one that could take down the electric grid, financial networks or energy plants.

Republicans say Obama has failed to slow Iran’s nuclear program, saying that it could spark an arms race across the Middle East and that it poses the greatest threat to the U.S. and its allies.

Sen. John McCain, the leading Republican on the Senate Armed Services Committee, told his party’s national convention that Obama missed an opportunity by not supporting a revolution in Iran.

“For four years, we’ve drifted away from our proudest traditions of global leadership,” said McCain, the GOP presidential nominee in 2008. “We are now being tested by an array of threats that are more complex, more numerous and just as deeply and deadly as I can recall in my lifetime.”

Others say that the Obama administration has calmed tensions overseas with Russia, China and other countries that viewed the American invasion of Iraq with suspicion.

“Everyone was afraid that Iraq meant that whenever we thought it was a good idea to bring democracy to a country by force we would do it,” said James Lewis, a Washington-based national security expert, now with the Center for Strategic and International Studies. Through diplomatic efforts by the Obama administration, he said that “that level of fear has been tamped down. The global perception of the U.S. is better.”

Lewis agreed that Iran may be the one place where the U.S. is no better off than it was four years ago, but he said things are stagnant, not worse. But he blamed the lack of progress on the Iranians and their refusal to engage.

Tensions with China continue over its growing military, as well as cyberactivities and the territorial disputes in the South China Sea. A trip to China this past week by Secretary of State Hillary Rodham Clinton highlighted the friction between Washington and Beijing.

But Clinton and other U.S. officials say that despite the routine disagreements, they can now discuss the issues more freely and frankly with the Chinese, unlike in recent years, when communications were difficult and rare.

“We have strengthened our alliances around the world to protect against future threats, locked down nuclear materials and improved our homeland defenses,” said Tommy Vietor, spokesman for the National Security Council. “The U.S. is absolutely safer now than four years ago.”