House Speaker Nancy Pelosi (D-Calif.) has long argued that impeaching President Trump would be bad for her party, so she won’t do it. And she’s successfully tamped down calls to change course, even if, privately, Democrats in her caucus disagree, report The Post’s Rachael Bade and Mike DeBonis.

But sooner or later, Pelosi may have to consider impeachment, her colleagues warn.

What could convince her to do that? Here are the options, ranked least likely (4) to most (1).

4. Impeachment becomes a more popular issue among independent voters: This is the top reason that Pelosi doesn’t want to consider impeaching Trump, even if, by her own admission, she thinks he’s doing more to deserve it. An April Washington Post-ABC News poll found a majority of Americans (56 percent) oppose impeachment, even as most say the report by special counsel Robert S. Mueller III shows Trump lied. Independents were pretty clear that Congress should not begin impeachment proceedings, at 59 percent.

Could this change in a way that makes Pelosi feel more comfortable, politically speaking?

Why this isn’t likely to change Pelosi’s mind: Public opinion about the Mueller report seems pretty set, and it’s hard to see what would change it. Maybe information uncovered by congressional investigations into Trump could jolt people out of the status quo. Which brings us to our next, not-very-likely event to change Pelosi’s mind on impeachment ...

3. Trump keeps stonewalling Congress: Earlier this month, Pelosi said that Trump is “becoming self-impeachable.” She was referencing how Trump is blocking all House Democratic investigations into him and his administration. “Every single day, whether it’s obstruction, obstruction, obstruction — obstruction of having people come to the table with facts, ignoring subpoenas, every single day, the president is making a case — he’s becoming self-impeachable, in terms of some of the things that he is doing,” she said.

House Speaker Nancy Pelosi (D-Calif.) said President Trump is “becoming self-impeachable,” pointing to his efforts to fight all subpoenas from congressional investigations and prevent key aides from testifying before Congress. (Washington Post Live)

If this continues, could Pelosi move to begin impeachment proceedings, as a way of signaling enough is enough?

Why this isn’t likely to change Pelosi’s mind: Trump is blocking 20 congressional investigations, a Washington Post analysis found. So with Pelosi steadfastly against impeachment today, it’s hard to see how this gets any worse in a way that convinces her she needs to change course.

2. Democrats get stalled in the courts: Trump’s blockade of Congress is forcing them to ask the courts to weigh in on their right to request his tax returns or the unredacted Mueller report or have his former aides, who were key witnesses for Mueller, come testify. To do that, the White House has to argue to judges that Congress is investigating things it has no right to.

Why this isn’t likely to change Pelosi’s mind: The first of many court battles began this week, and things look pretty good for Democrats. Trump has sued his accounting firm and Congress to prevent that firm from handing over his financial records — which some congressional investigators think may hide evidence of fraud. On Tuesday, a federal judge “expressed astonishment” that Trump would argue Congress has no right to investigate a sitting president. The judge noted that that would have stopped the Watergate and Whitewater investigations, which led to the resignation of a president and impeachment of another, writes The Fix’s Aaron Blake.

Why this could change Pelosi’s mind: Even if the Trump administration loses its court battles to withhold information from Congress, it could drag it out long enough for Pelosi to feel like Congress has no other option than impeachment to hold Trump accountable. Remember, she’s vowed to do something on that front, after a nearly two-year independent investigation could not exonerate Trump from obstructing justice.

1. Impeachment would help their case in court: One of Trump’s legal arguments against handing over information to Democrats is that they are a legislative body, not a judicial one. If it’s not for legislation (side note: Democrats say their request for Trump’s taxes is rooted in making policy), then they can’t request the information, his legal team argues.

That’s a questionable legal theory in some of these information battles, but legal experts say it holds up best as a way to prevent Congress from seeing the unredacted Mueller report. Grand jury information is typically kept secret except for relevant legal proceedings.

Why this is most likely to change Pelosi’s mind: Congress could turn themselves into a judicial body by beginning impeachment proceedings.

Natural Resources Committee Chairman Raúl M. Grijalva (D-Ariz.) got at this in an interview with Bade and DeBonis:

"At some point, as every committee gets stonewalled,” he warned. “The case for impeachment as a mechanism to get what we need . . . gets stronger and stronger.”

When they asked whether he thinks Pelosi will support impeachment eventually, Grijalva responded: “I think a lot of people are going to have to reconcile themselves to that.”