Former Labor Secretary and class warrior Robert Reich took to social media on Monday to sound the alarm about something "flying under the radar that you should know about."

There's a new directive from Trump, NSPM-7, or National Security Presidential Memorandum number seven, that Reich said, "could make it a crime to criticize him."

"In September, Trump ordered the Attorney General and the Secretaries of State, Treasury, and Homeland Security to implement new measures to 'counter domestic terrorism and political violence,'" he explained.

"Now, at first glance, this may sound reasonable. After all, we all oppose political violence. But the reality is far more dangerous: NSPM-7 hands the federal government sweeping power to target anyone who speaks out against Trump or his administration," warned Reich. "It’s a blueprint for criminalizing disagreement as 'terrorism.'"

The American Civil Liberties Union noted, "Like the president’s investigation into the Open Society Foundations and his order purporting to designate 'Antifa' as a 'domestic terrorist organization,' which is not a thing!), NSPM-7 is a deliberate attempt to sow fear and intimidate and silence opposition to the president’s abuses."

The FBI has already visited the home of someone who appeared at a protest under NSPM-7.

Reich called the language in the order "alarmingly reminiscent of the McCarthy-era witch hunts" of the 1950s, in which Sen. Joseph McCarthy (R-WI) threw around accusations about being a communist, as people were blacklisted, silenced, and fired over an allegation.

Trump's memo is "filled with the same kinds of vague, accusatory terms — 'anti-American, anti-capitalist, anti-Christian' — McCarthy once used to smear and destroy political opponents," said Reich. "Under these sweeping definitions, peaceful advocacy could be branded as extremism. A sermon, a protest sign, an op-ed in a student paper, or even a donation to a social justice or environmental group could be held up as 'evidence' of disloyalty."

He noted that Trump has already started using words to describe Democrats like “vermin,” “scum,” and “the enemy within.” He even went so far as to tell members of the Navy and Marines, “take care of this little gnat on our shoulder called the Democrats.”

"Such rhetoric isn’t just petty or divisive," Reich continued. "It’s highly dangerous, especially when paired with a presidential memo designed to give those words the force of law."

Reich closed by warning that memos like this from Trump aren't about terrorism or safety, but about silencing his critics under threats, investigations and even imprisonment. Any person who believes America has a right to "speak freely, worship freely and associate without fear" should contact their member of Congress to "intervene immediately."

This is "not democracy — it's a return to the darkest days of McCarthyism, when fear and accusation replaced freedom and truth."

Read the full comments here.