U.S. efforts to crack down on would-be terrorists – and specifically Islamic State sympathizers – have produced a series of arrests and prosecutions in recent months, most recently the arrest of a 23-year-old Massachusetts man in connection with a plot to carry out deadly attacks at college cafeterias.
Still, there are deep concerns such gains may not prevent another major terrorist attack.
The warning, given Wednesday to members of the House Homeland Security Committee, came as lawmakers grapple with ways to curtail the success of groups like the Islamic State in recruiting followers in the United States and around the world.
"The status quo of doing nothing with radicalized individuals or putting them away for 25 years is untenable," said Seamus Hughes, deputy director of the Program on Extremism at George Washington University's Center for Cyber and Homeland Security.
WATCH: Related video from VOA's Cindy Saine
Hughes, a former staffer with the National Counterterrorism Center, called the current U.S. approach shortsighted, arguing it consistently misses the chance to intervene with "individuals that are still persuadable before arrest, that are still reachable."
Other experts caution that the long-term failings of current U.S. strategy are even more dangerous.
"We know that the ideology of the extremists is impacting kids as young as 10," said Farah Pandith, a former director for Middle East Regional Initiatives at the National Security Council, now with the Council on Foreign Relations.
"The extremists are winning over youth from Detroit to Dhaka. They have a sophisticated, well-funded machine that is working 24/7 to persuade and provoke youth," Pandith said. "These children and young adults will continue the cycle of violence and fear."
Countering the message
The Department of Homeland Security said it has been partnering with local governments and community groups for almost a decade to help counter extremist messaging and recruiting and is asking for additional funding for some existing programs.
Most recently, U.S. efforts to counter extremist messaging and recruiting have largely focused on a Justice Department-led pilot project in three major urban areas: Boston, Los Angeles and the twin cities of St. Paul and Minneapolis in Minnesota.
Additionally, the Justice Department's proposed 2016 budget calls for an additional $15 million to pay for several additional programs to counter violent extremism.
Other countermessaging efforts, including some by the State Department using social media, have been slammed by critics who call them "laughable" for the lack of engagement.
House Homeland Security Committee Chairman Michael McCaul said Wednesday that although officials have made more than 60 arrests in the past year in connection with Islamic State-inspired plots, the U.S. is "nowhere near close" to reducing the threat of what he called "a new age of peer-to-peer terrorism."
"While extremist recruiters are moving at broadband speed, we are moving at bureaucratic speed," McCaul said.
Yet even if the government moves more quickly, experts say there is only so much it can do directly.
"Small seed grants from government can work if we're not putting the American flag over everything, if we find partners on the ground," said Pandith, of the Council on Foreign Relation.
She and others contend the U.S. and other governments would be best served by reaching out especially to millennials, those in their 20s and 30s who have grown up with social media and tend to be the most adept at finding effective ways to reach other young people.
Flow of fighters
The concerns, though, extend beyond the work extremists are doing in cyberspace to create an army of virtual supporters and sympathizers. Officials in the U.S. and Europe, especially, have also been focused on the link between extremist propaganda and the flow of foreign fighters to the conflict in Syria and Iraq.
U.S. counterterrorism officials say more than 3,700 Westerners have traveled to Syria and Iraq for jihad.
And while only about 200 U.S. citizens have traveled or attempted to travel there, in many of the arrests related to Islamic State-inspired plots, the suspects have at least talked about traveling overseas to join in jihad.
According to court documents released Monday, Adam Ciccolo, the 23-year-old man arrested for wanting to carry out a Boston Marathon-style attack at a college cafeteria, "expressed a desire to go overseas to fight" before settling on a U.S.-based plot.
In June, an Austin, Texas, man, Michael Todd Wolfe, 24, was sentenced to more than eight years in prison after pleading guilty of trying to travel to Iraq to join the Islamic State group.
And in May, U.S. officials arrested Nader Elhuzayel, 24, at Los Angeles International Airport, alleging he planned to travel to Istanbul, Turkey, so he could sneak across the border to Syria and join the Islamic State group.
'A draw, a magnet'
"The thing that is driving this is the conflict in Syria, and so over the long haul, as long as the conflict continues to go on, it's going to be a draw, a magnet for extremists from around the world," said former National Counterterrorism Center director Matthew Olsen.
And just like officials and analysts are concerned about those foreign fighters coming home with the intention of recruiting more followers or carrying out attacks in the short term, there is also the longer-term danger posed by children of foreign fighters, some of whom have been taken by their parents to Syria or Iraq and who are being inundated by extremist propaganda.
"They're raising children in an environment of really unprecedented, open violence," said terror analyst J.M. Berger. "The next generation that comes out of this community is going to be scarred, and we really don't know what to expect, whether they're going to continue what they were taught as children or whether they'll run away from it.
"It's an open question, but the human cost of ISIS is going to be substantial over generations," he said, referring to an acronym for the group.