A majority of Americans (57 percent) still think Trump committed an impeachable offense, which is essentially identical to the share who said so in mid-November when we first asked the question. There was one relatively small but noteworthy shift between the first and second rounds of our survey. After the first round of hearings, where witnesses testified that Trump and his allies had been involved in the push for investigations into Joe Biden and his son, respondents were more likely to agree that Trump withheld military aid to pressure the Ukrainians into opening an investigation. In our initial survey, 56 percent of respondents said they believed this happened, but in the latest poll, that number rose to 63 percent. Democrats are still, however, much more likely than Republicans to think that Trump conditioned the aid on the investigations.

Overall, though, opinion on impeachment seems to have hardened as a result of the public testimony instead of persuading people to change their position. For instance, a majority of respondents (58 percent) said that the hearings did shift their thinking on whether Trump committed an impeachable offense, but in almost all cases they simply became more convinced of their original opinion. Ninety-five percent of people who said the hearings made them more likely to think Trump committed an impeachable offense already said they thought he committed an impeachable offense in the first wave of our poll. Similarly, 95 percent of those who said the hearings made them less likely to think Trump committed an impeachable offense already thought his behavior wasn’t impeachable.1