The FBI is investigating some 850 cases of domestic terrorism and considers it serious and persistent threat, the FBI's Michael McGarrity told the House Committee on Homeland Security on Wednesday.
McGarrity and his fellow national security officials then went on to explain to committee members why the U.S. doesn't have an explicit law allowing the federal government to criminally charge extremists with domestic terrorism.
The federal government, law enforcement and even civil rights groups like the ACLU all consistently say that free speech rights under the First Amendment would make it problematic to define U.S. groups as terrorist organizations.
In an exchange with Democratic Congresswoman Yvette Clarke of New York, McGarrity noted that law enforcement has expanded powers when dealing with suspects linked to international terrorist groups like the Islamic State and al-Qaida.
"How does it give you more latitude?" asked Clarke.
"Because they're actually designated as a terrorist organization," McGarrity responded.