Republicans are treating U.S. law enforcement and national security agencies as adversaries, while treating a hostile foreign nation as a friend.

Four-star general Michael Hayden, former director of the CIA and NSA, issued a grave warning Monday night, telling CNN’s Don Lemon that partisan attacks on the FBI and other agencies are “chiseling away at institutions we are going to need again.”

Hayden made the remarks during a discussion about congressional Republicans’ failure to hold Donald Trump accountable for his attacks on democratic principles and institutions, from undermining special counsel Robert Mueller’s Russia probe to calling on the Department of Justice to investigate his political opponents.

“Congress has allowed the president to take a lot of their authorities,” Hayden said, noting that Congress is supposed to serve as a check on the power of the executive branch — but that Republicans don’t seem very interested in fulfilling that fundamental responsibility.

As Hayden noted, Trump’s GOP allies in Congress have sat back and watched as Trump undermines the agencies and officials conducting the Russia investigation. In many instances, Republicans have even joined in on Trump’s assault on U.S. institutions by slinging baseless accusations of wrongdoing at the FBI and undercutting the independence of the Department of Justice in an attempt to discredit their work.

But in their reckless partisanship, Republicans are inflicting lasting damage on the very institutions upon which our national security and democracy depend. Attacking our intelligence agencies — as Trump and many GOP lawmakers have done for the past year — diminishes their capabilities and not only does a disservice to Americans, but actually serves the interests of countries like Russia.

And one day, Republicans are going to look back on their actions with regret, Hayden warned.

“We are chiseling away at institutions we are going to need again,” he said.

Hayden’s remarks couldn’t be more timely.

On Monday, Republicans stood by silently as the deputy director of the FBI was forced out of his job after a months-long smear campaign led by Trump and his allies.

Later in the day, Republicans on the House Intelligence Committee voted to release an “intelligence memo” written by partisan hack Devin Nunes, but voted against letting the FBI brief Congress on the intelligence that supposedly informed the memo — a move that appears to be designed to provide cover for Trump, at the expense of career law enforcement officers

Then, to cap off the evening, Republicans watched as Trump defied U.S. law by refusing to enforce sanctions on Russia.

It’s hard to think of many things more shameful than what Republicans did on Monday — treat U.S. law enforcement and national security agencies as adversaries, while treating a hostile foreign nation as a friend.