The U.S. hasn’t experienced a 9/11-style attack since terrorists flew airliners into the World Trade Center and the Pentagon 13 years ago. But does that mean we’re any safer now? It depends on who you ask.

America has improved homeland security -- a term that wasn’t even around before Sept. 11, 2001 -- and there’s more coordination among intelligence agencies to counteract terrorist threats. But the rise of the Islamic State, formerly known as ISIS, and the surge in foreign fighters joining the terror group has also increased the risk of another massive terrorist attack. 

Only 26 percent of Americans polled in an NBC News/Wall Street Journal survey last week said the country is safer now compared with before Sept. 11, 2001. The same percentage said the U.S. is about as safe as it was then. Nearly half said the U.S. is less safe.

"Over the last several years, we have consistently taken the fight to terrorists who threaten our country," President Barack Obama said in a speech to the nation describing his plan to wipe out ISIS Wednesday night. "We took out Osama bin Laden and much of al Qaeda’s leadership in Afghanistan and Pakistan. We’ve targeted al Qaeda’s affiliate in Yemen, and recently eliminated the top commander of its affiliate in Somalia. We’ve done so while bringing more than 140,000 American troops home from Iraq, and drawing down our forces in Afghanistan, where our combat mission will end later this year. Thanks to our military and counterterrorism professionals, America is safer. Still, we continue to face a terrorist threat. We cannot erase every trace of evil from the world, and small groups of killers have the capacity to do great harm."

Victor Asal, an associate professor of political science at the University at Albany in upstate New York, said assessing whether America is any safer is complicated.

“I think that in some ways we’re more secure,” he said. “Before 9/11, we weren’t really focusing on terrorism as a threat.”

The U.S. Transportation Security Administration, one of the federal agencies created after the Sept. 11 attacks, is making airplane travel safer with stringent security screenings at U.S. airports and the deployment of federal air marshals. Asal said that the U.S. also now has “more serious regard for radicalization” within the country.

But the wars in Afghanistan, and particularly Iraq, have bred new terrorists in places where they didn’t exist before Sept. 11.

“The United States has launched two wars that have created a tremendous amount of hostility towards the U.S.,” Asal said. “On average, we’re safer but we’ve also stirred the pot in certain areas.”

The next terrorist attack on American soil is more likely to mirror the Boston Marathon bombing in April 2013, when authorities said Russian-born brothers Dzhokhar and Tamerlan Tsarnaev detonated pressure cooker bombs packed in backpacks placed at the race’s finish line, security experts said.

There have been other attacks since 2001. Most notably, U.S. Army Maj. Nidal Hasan killed 13 people in 2009 when he opened fire at the base in Fort Hood, Texas. An Army psychiatrist, Hasan sympathized with Islamic extremists and admired Anwar al-Awlaki,, a U.S. citizen who played a major role in al Qaeda’s organization in Yemen.

There also been various terrorist plans that were thwarted, including efforts to attack Los Angeles, Times Square, John F. Kennedy International Airport, the New York City subway system, a Detroit-bound airliner and the Sears Tower in Chicago, among others that have been made public.  

“The likelihood of another Sept. 11 is very rare, but it’s not zero,” Asal said. “If it happens though, it’s a game-changer.”

Michael O’Hanlon, a senior fellow at the nonpartisan Brookings Institution, a Washington public policy center, said Americans should feel safer given the many security improvements since 2001.

“I think the answer is ‘yes,’ but it’s debatable,” he said. “On balance, I would say we are not in greater danger.”