President Trump’s war on CNN has moved from Twitter to the courtroom. At a raucous post-election press conference in which Trump railed at CNN chief White House correspondent Jim Acosta and called him a “rude, terrible person” for asking tough questions, the White House suspended Acosta’s press credential. Acosta and CNN then sued, arguing that, under longstanding precedent, the White House’s retaliation violates the First Amendment.

But this goes beyond one reporter’s press pass. It’s part of a pattern of conduct that constitutes an impeachable offense.

"Make no mistake: President Trump’s war on the press endangers the country. As strongman leaders in declining democracies like Turkey and Hungary have discovered, an authoritarian ruler can undermine the freedom of the press by measures short of direct censorship."

The Constitution empowers Congress to impeach the president for “high Crimes and Misdemeanors.” Contrary to a common misunderstanding, this formula is not limited to prosecutable crimes, like obstruction of justice; indeed, in the constitutional debates, the Founders themselves repeatedly gave examples of impeachable offenses that were not crimes. In the words of Supreme Court Justice Joseph Story, the impeachment power has a “more enlarged operation.” Its purpose is not to punish the impeached official, but rather to protect the country against his misconduct.

And make no mistake: President Trump’s war on the press endangers the country. As strongman leaders in declining democracies like Turkey and Hungary have discovered, an authoritarian ruler can undermine the freedom of the press by measures short of direct censorship.

Trump does this in four main ways: Like President Richard Nixon, who pressured the Internal Revenue Service to audit the tax returns of journalists on his “enemies list,” Trump threatens to use federal law enforcement to punish the press for critical coverage. He pressures private news businesses to fire particular reporters or editors. He tries to use federal regulatory power to retaliate against critical press, whether by suspending a press pass, blocking a proposed merger, or revoking TV stations’ licenses. And on the taxpayer’s dime, he constantly demonizes the press as “fake news,” or with the Stalinesque smear “enemy of the American People.”

Many presidents have tangled with the media. But the Supreme Court has long acknowledged that a government official’s “threat of invoking legal sanctions and other means of coercion, persuasion, and intimidation” violates the First Amendment. How do we know when a president’s war on the press crosses the line into an impeachable abuse of office?

The answer may lie in a remarkable bipartisan resolution that the Senate passed in August. At the time, it attracted little fanfare. But it lays the groundwork for impeaching Trump for undermining freedom of the press.

The resolution, which the Senate approved with unanimous consent, starts off innocuously. It cites Ben Franklin, Thomas Jefferson, James Madison, Ronald Reagan, the Supreme Court, and the Constitution itself for the uncontroversial idea that the free press is “integral to the democratic foundations of the United States.”

During normal times, this would not be controversial. But these are not normal times. And this is not a normal resolution. It’s aimed squarely at Donald Trump.

The Senate declares four key points. First, it directly rebukes Trump by insisting that “the press is not the enemy of the people.”

Second, the free press serves a “vital and indispensable role” in advancing “the most basic and cherished democratic norms and freedoms of the United States”—norms and freedoms that are repugnant to Donald Trump.

Yet the Senate has just gotten started. It “condemns the attacks on the institution of the free press and views efforts to systematically undermine the credibility of the press as an attack on the democratic institutions of the United States.”

"Impeachment is well suited to address a president whose distaste for the foundational institutions of our democracy is so strong that he endangers our most basic freedoms."

Read that again. The Senate views efforts to systematically undermine the credibility of the press as an attack on the democratic institutions of the United States.

The Senate concludes that “it is the sworn responsibility of all who serve the United States by taking the oath to support and defend the Constitution of the United States”—such as the president—“to uphold, cherish, and protect the entire Constitution, including the freedom of the press.” Yet obviously Trump is not doing this.

In short, the Senate has concluded that Donald Trump is violating his oath of office and undermining the Constitution itself. Impeachment is well suited to address a president whose distaste for the foundational institutions of our democracy is so strong that he endangers our most basic freedoms. Indeed, in 1926, the House impeached a federal judge for, among other things, “threatening to jail a local newspaper editor for printing a critical editorial.”

Some people think impeachment depends on Special Counsel Robert Mueller. But that’s a mistake. The Senate has stated for the record, in a bipartisan resolution passed without a single objection, that Trump is violating his oath of office and engaging in “an attack on the democratic institutions of the United States.” That’s a ground for impeachment, and it’s time for Congress to start the hearings.