House Intelligence Committee Chairman Adam Schiff (D-Calif.) speaks with reporters after his panel voted in a closed session to send more than 50 interview transcripts to special counsel Robert S. Mueller III. (J. Scott Applewhite/AP)

For weeks, President Trump has been warning Democrats not to investigate him and his administration too aggressively. He repeated that message at Tuesday’s State of Union: “An economic miracle is taking place in the United States, and the only thing that can stop it are foolish wars, politics, or ridiculous partisan investigations.”

House Democrats are clearly not cowed. In fact, quite the opposite.

On Wednesday, House Judiciary Chairman Jerry Nadler (D-N.Y.) promised a high-profile grilling of acting attorney general Matthew G. Whitaker. Nadler sent Whitaker a letter two weeks ago asking him which areas Trump would claim executive privilege about concerning their interactions. Nadler now says he has received no response by his deadline and expects Whitaker to “provide full and complete answers."

But just in case, he is also moving forward Thursday with a subpoena to compel Whitaker’s testimony. That move drew a rebuke this week from the ranking minority-party member of the committee, Rep. Douglas A. Collins (R-Ga.), who called it a “dangerous precedent” to subpoena witnesses who have agreed to voluntarily testify.

The gambit does run counter to how these things have been handled in the recent past. Republicans largely just allowed Trump administration officials not to answer such questions without formally invoking executive privilege. In past administrations, executive privilege was used as a bargaining chip to avoid a legal fight. Nadler isn’t bothering with any of that.

All of it is geared toward disarming Whitaker ahead of time if and when he does claim privilege. And it suggests that Nadler is loaded for bear.

Also Wednesday, House Intelligence Committee Chairman Adam B. Schiff (D-Calif.) laid out an extensive — and expansive — outline for how his committee will resume its probing of Russia. Schiff laid out five areas of inquiry. They include the ones you would expect and are familiar with because of special counsel Robert S. Mueller III’s investigation: Russian interference, potential collusion and potential obstruction of justice.

But then there are Nos. 3 and 4:

  • "(3) Whether any foreign actor has sought to compromise or holds leverage, financial or otherwise, over Donald Trump, his family, his business, or his associates.” 
  • “(4) Whether President Trump, his family, or his associates are or were at any time at heightened risk of, or vulnerable to, foreign exploitation, inducement, manipulation, pressure, or coercion, or have sought to influence U.S. government policy in service of foreign interests.” 

This is something Democrats including Schiff have been previewing for a while, but now it’s officially a major part of the committee’s purview. And the broad berth he has given himself suggests that he’s ready to go after any number of things: Trump Tower Moscow, the claims in the Steele dossier about Russian kompromat on Trump, Trump’s highly secretive talks with Russian President Vladimir Putin, Trump’s business and its foreign entanglements, the Trump Organization and even Trump’s family, which Schiff mentions specifically.

Schiff is now actively and officially pursuing the idea that the president of the United States is a compromised man, and he made that clear shortly after Trump warned against overzealous investigations.

It’s always been a given that Democrats would pursue some investigations, but the scope and tactics are important. And there are pitfalls involved, most notably if they go too far — possibly by impeaching Trump. The likes of House Speaker Nancy Pelosi (D-Calif.) and Nadler (who would be in charge of impeachment proceedings in the House) have been cautious about broaching the i-word and being seen as prejudging anything.

And Trump has suggested that he’ll fight fire with fire — maybe even by somehow launching investigations of Democrats. On Wednesday, the president called Schiff’s newly detailed probe “presidential harassment.”

“He has no basis to do that,” Trump said. “He’s just a political hack.”

Pelosi said Wednesday that Democrats won’t give in to what she labeled Trump’s “threat.”

“It’s our congressional responsibility, and if we didn’t do it, we would be delinquent in that,” she said. Schiff added that Democrats are “not going to be intimidated or threatened."

These moves — taken shortly before and after Trump issued that “threat” — suggest that it’s not just talk. No, they were never going to listen to Trump and just back down. But all this suggests they are more than emboldened and are ready to play hardball.