Robert Mueller has just resigned as special counsel. The Russia investigation is over—well, his is, anyway. But he did leave a parting gift that will likely infuriate House Speaker Nancy Pelosi.

During his brief statement, Mueller again highlighted one of the most controversial findings of his special counsel report regarding obstruction of justice, saying that, “If we had had confidence that the president did not commit a crime, we would have said so.” Mueller went on to say, “We did not, however, make a determination as to whether the president did commit a crime.”

None of this is new information, of course, but that fact did not stop Democrats on Capitol Hill and beyond from calling on Congress to begin impeachment proceedings, something Pelosi and House leadership have been against for some pretty straightforward political reasons. Rep. Alexandria Ocasio-Cortez (D–N.Y.) said Mueller is playing Taboo, a game where you must describe a word without using it, and that the word is impeach.

Mueller is playing a game of Taboo with Congress. His word is “impeach.” https://t.co/mS4K8faLCw — Alexandria Ocasio-Cortez (@AOC) May 29, 2019

Meanwhile, on the 2020 presidential campaign trail, Sen. Cory Booker took to Twitter to suggest that Mueller’s statement “makes it clear” that impeachment should occur now.

Booker is a low-tier candidate, but he joins Sen. Elizabeth Warren, who is not alone in this call. This could start to break the floodgate. Should the rest of the candidates follow suit, Pelosi and House leadership will be on an island, facing almost the full fury of the Democratic Party. It’s Nancy’s House, but that will be a lot of pressure.

Robert Mueller’s statement makes it clear: Congress has a legal and moral obligation to begin impeachment proceedings immediately. — Cory Booker (@CoryBooker) May 29, 2019

Why Mueller, who has been sphinx-like for two years, decided to announce his resignation in that way, and with his statement about not being able to clear Trump on obstruction, is hard to say. Maybe Ocasio-Cortez is right and this is a wink to the House Democrats, saying basically, I had the goods on him but Department of Justice policy says I couldn’t indict.

Mueller also could have been covering his tail and reputation with the remarks. The president took them as a win, tweeting that it was “case closed,” as did many conservatives in the media and social media. We had already read these words in the report, so why does Mueller saying them at a microphone change their meaning or how Democrats should react?

But whatever Mueller’s intent was today, he poured gasoline on a fire Pelosi is desperately trying to put out. Generally speaking, when this happens, Pelosi’s approach is to amp up her personal attacks to appear tough while avoiding impeachment. But that may not be enough this time. House investigations are already ongoing. The next tool in the shed is an impeachment inquiry, and it’s difficult to believe that, should that occur, Democrats would land anywhere but eventually impeaching Trump.

At least, for now, this is still her call, but she hasn’t turned the corner on her caucus’s demand for impeachment. Key allies like House Judiciary Committee Chairman Jerrold Nadler have stayed on the farm so far. Nadler issued a harshly worded response to Mueller’s statement insisting on investigation, but stopped short of calling for impeachment

Pelosi is not entirely isolated yet, but her circle is getting smaller. She is convinced Trump craves impeachment, and she may have no choice but to give it to him.