Why can't the government stop US jihadists?

This is a rush transcript from "The Kelly File," October 6, 2014. This copy may not be in its final form and may be updated.

MEGYN KELLY, HOST: Judge Andrew Napolitano is our Fox News senior judicial analyst.

So, they were in Syria fighting with our enemies against us and against our allies and yet we're going to track them carefully when we allow them to come back in the United States. Can we charge them with treason, Judge?

JUDGE ANDREW NAPOLITANO, FOX NEWS SENIOR JUDICIAL ANALYST: Well, I'm shaking my head. Because I like you like most people in the legal community have a great deal of respect for Jim Comey, the FBI director.  And what he said earlier in your first segment was true and profound and I'm glad he said it. But he forgot that there's a statute called providing material assistance to a terrorist organization.

So, if he knows that Americans have been fighting with ISIS and he also knows that the secretary of state has declared ISIS a terrorist organization. That is more than enough evidence for him to arrest them upon their re-entry into the U.S. It is crazy to let them back in and wait and see what they do. It's also a waste of FBI resources. And the director most respectfully -- he's a fine lawyer and a wonderful person -- should be aware of that.

KELLY: Well, and who knows whether he's setting policy on this. But it is crazy.

So, we've identified them by name fighting in Syria with ISIS, a terrorist organization. And we are going to "track them carefully" when they come back into America with their U.S. passports?

I looked it up. You know what? The secretary of state can revoke your passport or at least limit it, revoke or limit it they say, when, "for example, they determine that you are in arrears of child support payments." Child support, Judge. That they can take your passport away, but if you take up the jihad with ISIS we're just going to track you carefully.

NAPOLITANO: You know, I have a problem with his being hung up on the issue of the passport. The issue is not the passport. The issue is their freedom to move around in the United States of America after they have left training for some terrorist organization which is in and of itself a federal crime. That is more than enough to arrest them, charge them, indict them and keep them from traveling free around the United States, whether they have a passport or not. He knows he can arrest them at JFK or Dulles or anywhere they first land in the United States. And they'll never be free because a grand jury will indict them immediately.

KELLY: Right. Because the other thing that you can revoke somebody's passport on, if you want to go back to the passports, if there's an outstanding federal arrest warrant for the person holding the passport.

So, why don't we just get arrest warrants going out, but this ISIS fighters, the Americans who went jihadi on us, and arrest them when they return to the United States?

NAPOLITANO: If he knows who they are as he says he does, and I accept him at his word.

KELLY: He says he does.

NAPOLITANO: That is more than enough for his agents to file an application for an arrest warrant and it will be granted. And then they would be held in jail until they were indicted.

KELLY: Is it treason? A lot of the viewers think that this is treason.

NAPOLITANO: Technically, it is not treason. The Constitution of the United States provides a very high bar for treason. It means that you provided aid and comfort to the enemy by fighting against the United States. And the enemy is what Congress is declared, not what Barack Obama has declared as the enemy.

So the president by refusing to seek a declaration of war against these people has taken treason off the table.

KELLY: Unbelievable. Judge, good to see you.

NAPOLITANO: Good to be with you, Megyn.

Content and Programming Copyright 2014 Fox News Network, LLC. ALL RIGHTS RESERVED. Copyright 2014 CQ-Roll Call, Inc. All materials herein are protected by United States copyright law and may not be reproduced, distributed, transmitted, displayed, published or broadcast without the prior written permission of CQ-Roll Call. You may not alter or remove any trademark, copyright or other notice from copies of the content.