On Tuesday, The Washington Post released a new poll evaluating how Americans view the impeachment inquiry underway in the House. Since we last polled on the question in July, there was a substantial increase in support for an inquiry, across partisan groups.

That increase looked like this.

When I shared that graph on Twitter, there was a common response: This proves House Speaker Nancy Pelosi’s decision to embrace an inquiry, a step she took Sept. 24, shifted public opinion.

It doesn’t. It certainly doesn’t disprove Pelosi’s role, of course. It’s just … murky.

There is no question that polls after Pelosi’s announcement show more support for an inquiry than polls did beforehand. Using poll data aggregated by FiveThirtyEight, we can see that clearly. At the end of July, support for an impeachment inquiry was in the 30-to-40-percent range. After Pelosi’s announcement, it is over 50 percent.

But Pelosi’s announcement did not happen in a vacuum. She did not just wake up one morning and think, Sure, today, why not. Instead, she was reacting to news that a whistleblower had raised questions about President Trump’s interactions with the president of Ukraine. One day after Pelosi’s announcements, a rough transcript of a call between the two presidents was made public. The following day came the full whistleblower complaint.


In other words, the launch of an impeachment probe overlapped with new evidence that Trump had both asked a foreign leader for political assistance and that the White House had tried to bury information about that request.

Quinnipiac University polled right before and right after those three events. Before the three, support for impeaching Trump and removing him from office was at 37 percent. Immediately after, it was at 47 percent — and support for an inquiry topped 50 percent. On Tuesday afternoon, Quinnipiac released another new poll, showing support for an inquiry and for removal had not changed much.

It is hard to say Pelosi, rather than the new evidence, caused that jump. Support for impeachment and removal among Democrats jumped from 73 percent to 90 percent before and after the key days in Quinnipiac’s polling. Support among independents jumped 8 points, from 34 percent to 42 percent. Within each group, support rose about 23 percent, though one would assume independents would be less compelled by Pelosi’s seeming change of heart.

There is some suggestion that support for removing Trump from office spiked and then faded a bit. In both Quinnipiac and YouGov polling, support for removal was higher closer to when the Ukraine news broke than it is now. Generally, though, the trend line has not ticked upward very much over the course of the year, particularly when compared with support for an inquiry.

These polls certainly do not indicate Trump is in the clear on impeachment, either. That increase in support for an inquiry suggests a greater willingness to evaluate Trump’s behavior, which probably should not be considered a political win for the president.

We are in a moment, in short, when we have enough polls to be able to craft rhetoric but too few to figure out where things are headed and why. Polls are never more than a snapshot, and we are just starting to assemble the ones we have into something of a filmstrip.

Here is a reminder I often give myself: Use caution.