(CNN)President Donald Trump tweeted Sunday that the United States will designate Antifa as a terrorist organization, even though the US government has no existing legal authority to label a wholly domestic group in the manner it currently designates foreign terrorist organizations.
Current and former government officials say it would be unconstitutional for the US government to proscribe First Amendment-protected activity inside the US based on simple ideology. US law allows terrorist designations for foreign groups since belonging to those groups doesn't enjoy the same protections.
Antifa, short for anti-fascists, describes a broad group of people whose political beliefs lean toward the left -- often the far left -- but do not conform with the Democratic Party platform.
Antifa positions can be hard to define, but many members support oppressed populations and protest the amassing of wealth by corporations and elites. Some employ radical or militant tactics to get out their messages.
An additional problem with the President's claim is that groups who identify as Antifa are amorphous and don't have a central leadership, though some local activists are highly organized, according to federal law enforcement officials. That has made it difficult for US law enforcement to deal with violence from members of groups that label themselves as Antifa.
The President's call for a terrorist designation comes as Trump and Attorney General Bill Barr have pointed to far-left groups as responsible for many of the violent protests across the country.
Federal law enforcement officials told CNN they are aware of outside groups who are behind some of the property destruction and violence, using the cover of the legitimate protests in Minneapolis and elsewhere. Those domestic extremist groups include anarchists, white supremacists and far-left extremists, some of whom have overlapping affiliations.
An announcement by the Justice Department on Sunday to use Joint Terrorism Task Forces around the country to investigate some of the violence in major cities singles out leftist Antifa activity, though US law enforcement officials say there are groups from both the extremist left and right involved in the riots and attacks on police.
Trump's and Barr's focus on left-leaning groups also stands in contrast with repeated warnings in recent years from US law enforcement that the rise of white supremacist groups has become the biggest domestic terrorism challenge. Christopher Wray, the FBI director, has raised concerns about the increase of white supremacist activity driving the domestic terror threat -- in some cases surpassing that from foreign terrorist groups.
In response to the President's tweet, ACLU National Security Project Director Hina Shamsi said there is "no legal authority for designating a domestic group" as a terrorist organization.
"As this tweet demonstrates, terrorism is an inherently political label, easily abused and misused. There is no legal authority for designating a domestic group. Any such designation would raise significant due process and First Amendment concerns."
The Justice Department has studied the issue of creating a domestic terrorism law to apply to people involved in violence and who belong to domestic extremist groups, but the constitutional issues have been a hurdle to that effort.
Despite threats by the President to designate various groups as terrorists, the closest the Trump administration has come is, in recent weeks, the State Department's designation of a white supremacist group called Russian Imperial Movement, which is a foreign group but has some domestic US supporters, as a specially designated global terrorist group.
