It’s probably the most common question on the lips of Democrats and liberals across the country. Whether it’s the commentariat on cable news shows or protesters marching in the streets, they all want to know one thing. What are we waiting for? When are you going to impeach Trump? The answer to that question can be summed up in two words: Nancy Pelosi. Unless and until the Speaker is ready to move forward, it’s almost certainly not going to happen. Thus far she’s been playing this cautiously, but as Politico is reporting, things were heating up last night to the point where she might not be able to hold off her own caucus much longer.

House Democratic leaders sparred internally on Monday over whether to begin an impeachment inquiry against President Donald Trump, with Speaker Nancy Pelosi and her allies rejecting the call to move forward for now, according to multiple sources. Reps. David Cicilline (D-R.I.), Jamie Raskin (D-Md.), and Joe Neguse (D-Colo.) — all members of the Democratic leadership — pushed to begin impeachment proceedings during a leadership meeting in Pelosi’s office, said the sources. Pelosi and Reps. Rosa DeLauro (D-Conn.), Ben Ray Lujan (D-N.M.), Hakeem Jeffries (D-N.Y.) and Cheri Bustos (D-Ill.) — some of her key allies — rejected their calls, saying Democrats’ message is being drowned out by the fight over possibly impeaching Trump. Raskin — a former law professor — said he wasn’t advocating impeaching Trump but suggested that opening an impeachment inquiry would strengthen their legal position while allowing Democrats to move forward with their legislative agenda.

So what’s holding Pelosi back? Keep in mind that the Speaker has been knocking around Washington politics for a long time. A very long time. And she knows how this game is played. She’s seized the Speaker’s gavel twice now and the political highway is littered with the figurative corpses of those who went up against her. Some of the younger Democrats might want to keep that in mind.

Pelosi has two answers at her disposal, one for public consumption and one she’d probably rather not talk about. The convenient talking point is to say that starting any sort of action on impeachment would distract from the party’s issue messaging, along with that of their various primary candidates. They don’t want to be seen as the party that’s just out to “get Trump.” They want to talk about the issues and offer solutions. It’s really not a bad point to make, assuming she can get the rank and file to go along with it.

But underneath that marketing strategy, Pelosi knows this game well enough that a more pressing explanation is lurking. Trying to remove Donald Trump from office via impeachment would fail spectacularly and would paint the Democrats as a vindictive bunch of sore losers. And it could very well hand President Trump a second term on a silver platter.

It’s not even a sure thing that you could get enough Democrats in the House to vote for impeachment, particularly those from red and purple states. If you call the vote and it fails it’s a major embarrassment. And even if the measure passes, you’d need 67 votes in the Senate to pull this off. The Democrats (and their allies) currently hold 49 seats in the upper chamber. Do you really think there are 18 Republicans ready to vote to remove Trump? (And, again, that’s assuming you can get every Democrat in the Senate to vote with you. That is not at all a sure thing.)

If the Democrats try this, the rest of the agenda will grind to a halt and the news cycle will settle into endless coverage of their failed attempt to remove the President. Nancy Pelosi knows this. Unfortunately, many in her caucus haven’t figured it out yet.