In the past week, there's been repeated speculation that views on impeachment have solidified with partisans retreating to their separate corners and little room for movement. It's partly right—partisans left and right have largely come home. But the idea that there's not a healthy swath of persuadable voters across the country greatly exaggerates the reality. While an NPR headline Tuesday asserted, "Americans overwhelmingly say impeachment hearings won't change their minds," that seemed to misread the data. The NPR/PBS/Marist poll found that although 65% of Americans said they couldn't imagine anything that would change their mind on impeachment, 30% said they could imagine something changing their minds and another 6% said they weren't sure. That's a little more than a third of Americans who aren't sure about their view on impeachment.
The poll, conducted Nov. 11-15 (before this week's testimony) also found that 70% of Americans say a president asking a foreign leader to investigate a political opponent is "not acceptable" (just 22% said it was acceptable). That said, Americans are almost evenly split on impeaching Trump, 47% in favor, 46% opposed.
The biggest problem for Democrats isn't that no one is persuadable on impeachment, it's that the undecideds are generally paying less attention to the impeachment proceedings. A panel survey this week from FiveThirtyEight/Ipsos found, "Only about 34% of respondents who aren’t as certain about their stance on impeachment are following the process somewhat or very closely, compared to 66% of respondents who are more certain. So while there are people out there who could still be convinced by the Democrats’ case against Trump, they’re also less likely to be paying attention."
But that same survey indeed found that that while 42% of people were "absolutely certain" about their opinions on impeachment, about a quarter are uncertain about whether Trump's actions are impeachable. As FiveThirtyEight wrote, "a significant chunk of Americans are still persuadable when it comes to impeachment."