AMNA NAWAZ: An attempted bombing in New York City is raising questions about terrorism threats and security measures to prevent them.

The Department of Justice charged two young men from Pennsylvania, 18 and 19 years old, both of whom, authorities allege, say they were inspired by ISIS.

They're accused of bringing two homemade explosives to an anti-Islamic demonstration outside Mayor Zohran Mamdani's residence on Saturday and throwing one into the crowd.

The device didn't detonate and there were no injuries, but the incident highlights the challenge for security agencies at the same time funding for the Department of Homeland Security is uncertain.

For more on this, I'm joined by Juliette Kayyem of the Homeland Security Project at Harvard's Kennedy School.

She previously served as assistant DHS secretary during the Obama administration.

Juliette, welcome back to the "News Hour."

I want to note, given their composition, these devices could have caused much more damage had they detonated, but the alleged links to ISIS in this case, what strikes you about that?

What questions do you have there?

JULIETTE KAYYEM, Former U.S.

Department of Homeland Security Assistant Secretary: And that's exactly right.

You had a very sophisticated, deadly IUD.

This is not something that you just sort of wake up and build.

It had materials that would -- TATP, which is just basically -- if they had detonated, would have been deadly to over at least 100 people, protesters and counterprotesters in front of Gracie Mansion.

They didn't, fortunately.

The two teenagers -- and this is the challenge.

They said -- they get radicalized online by ISIS.

They have no criminal record, no outward sort of statement that they're about to do this.

They get in a car with these devices and then try to wreak havoc, a very violent, serious, attempted attack.

That -- those two stories are really hard for law enforcement to get a handle on because you have the radicalization, but sort of no ties, no conversations, no nexus to any group.

It's just the atmospherics of radicalization that we see across the board in terrorism now and, of course, we're more worried about in terms of Islamic-related terrorism because of the war in Iran.

AMNA NAWAZ: I want to ask about the war in a moment, but to follow up on that idea you mentioned, you wrote about this in "The Atlantic" today, and you said this.

"The challenge of Islamic terrorism in America is that, just like the homegrown terrorism of white supremacists, the radicalism is often diffuse."

How does that complicate authorities' ability to detect it and track it or disrupt it?

JULIETTE KAYYEM: Yes, so I started in counterterrorism before September 11, certainly was a part of that.

So, at that stage, you're looking for individuals with direct ties to al-Qaida or an organization that you know.

They're making phone calls, they are traveling, they're getting training, they're buying things that might disclose them.

And that was the apparatus that was built.

Fast-forward almost 25 years, you now have a radicalization process, teenage young men generally online a lot, feeding their anger, feeding isolation.

And while this is particularly related to the radicalization that ISIS uses, which is just diffuse, they're just saying go out and wreak havoc.

It's not directed towards anyone or anything in particular, but it is very similar to almost all kinds of terrorism we see today, whether it's right or left, international or domestic.

And it's that sort of amorphousness of it that makes it very hard to get a handle on and let alone stop before the guy who was able to -- as the picture we all saw, is able to throw the bomb into the crowd.

AMNA NAWAZ: You mentioned this moment, of course, more concerns with the U.S.

war in Iran.

I want to ask you about another story that we're following, which was news of a shooting at the U.S.

Consulate in Toronto just this morning.

We don't have many details yet, but there are concerns about U.S.

facilities, U.S.

assets being targeted at this moment as the war in Iran goes on.

How are you looking at this?

What do we know?

JULIETTE KAYYEM: Yes.

So I think we're deluding ourselves to think that this is just a regional war.

It's a regional war with global consequences.

We're seeing it in the economy.

We're seeing it with oil.

And now we're going to see it -- we're starting to see it with violence.

There's no -- and it's both the amorphous kind of violence that I just spoke about, so we don't know who's responsible for the Toronto shooting.

I would suspect that it -- I won't guess, but I would say you want to investigate this as possibly being tied to anti-American animus, but you also have the threat of state-sponsored terrorism.

I mean, when we talk about Iran's capability to fight back in the Persian Gulf or to protect itself, this is a nation that has used state sponsorship of terrorism as a tool of its aggression, whether it's Hezbollah or planned attacks in the United States or against individuals.

The idea that they're going to give up on that effort is, I think, naive.

And I think that we are -- it is right to view ourselves in a heightened threat environment, both as Americans in the homeland, but also, of course, throughout the world.

AMNA NAWAZ: In the minute or so we have left, I need to ask you about this moment when DHS funding is caught up in this partial government shutdown.

We know there's a budget strain there.

We have seen it show up at the airports, right, with TSA agents calling out and very, very long lines at multiple airports across the country.

How is that funding lapse, if it is, showing up in counterterrorism efforts?

JULIETTE KAYYEM: Yes, it very much is.

I mean, DHS is simply broken right now because not just the funding, but obviously the former Secretary Noem is out.

They don't have a confirmed secretary.

So you don't really have leadership.

Here's the irony of what's going on at DHS.

The thing that kept them from being fully funded, the border enforcement, the immigration stuff, that's still funded.

And it's the pieces that the Trump administration were essentially ignoring counterterrorism, cyber and the cyber threats that we may be facing from Iran, FEMA and emergency management, those pieces are the ones that -- a lot of them are not being funded.

So it's very bad for Homeland Security, for the department, as we battle over the funding mechanism.

But it's not a department that can rise to the occasion, given the risk and threat environment simply because, and the same thing we're seeing with TSA.

Those parts of the department, it's a big department, the ones not related to border and immigration enforcement, those are the ones that are not being funded.

AMNA NAWAZ: Juliette Kayyem of the Homeland Security Project at Harvard's Kennedy School.

Juliette, thank you.

JULIETTE KAYYEM: Thank you.