Public Opinion

Confidence in Mueller’s Investigation: May Update

By Mieke Eoyang, Ben Freeman, Ryan Pougiales, Benjamin Wittes
Thursday, May 16, 2019, 8:00 AM

From April 30 to May 2, we conducted a nationwide survey asking respondents a series of questions regarding Special Counsel Robert Mueller’s investigation. This survey was the third in a series; we conducted corresponding surveys immediately before the delivery of the Mueller report and after Attorney General William Barr’s summary letter. We are conducting this series to gauge how the report’s release and subsequent media coverage affects the public’s opinion of the investigation. These polls reveal a dramatic increase in confidence in Mueller’s investigation, driven in large part by a reversal in Republican respondents’ opinions of Mueller and the investigation. But equally dramatic are results that show the public, with the exception of Republicans, believes Mueller’s findings are damaging for Trump or they are split on this question and that additional investigation is needed.

Confidence in Mueller Remains High But There Are Signs of Renewed Partisan Sorting

Before and after Mueller delivered his report to the attorney general, and again in late April/early May, we used Google Surveys to ask respondents several questions about the integrity of Mueller’s investigation. For the most recent survey, question wording was modified slightly to reflect that the Mueller report had been publicly released. Specifically, we asked:

The questions elaborate on a question we ask in our monthly polls on confidence in government on national security matters, wherein we ask one confidence question on Mueller’s fairness and objectivity. The first question we asked in this series of surveys is the same question we’ve asked every month since October 2017. On our scale—which ranges from a score of 1, not at all confident, to 5, completely confident—the average confidence score for this question has hovered around or just below 3, indicating the public has modest confidence in Mueller. Average confidence in Mueller’s fairness and objectivity was 3.11 in the pre-report poll, which was up from 2.89 in our February monthly poll; it jumped to 3.40 in the post-report poll; and then it receded insignificantly to 3.39 in our third poll that concluded on May 2.

The average confidence number rather understates the drama of the change in confidence in Mueller over the past two months. Consider, for example, the change in “high confidence” (defined as 4 or 5 on the 1–5 scale). High confidence in Mueller’s fairness and objectivity stood at 43 percent immediately before the report was delivered on March 22, it increased to 51 percent after the Barr summary and it inched up to 52 percent in the third poll. Underneath this steady increase in confidence is volatility along partisan lines. The share of Republicans with high confidence in Mueller jumped from 19 percent to 55 percent from before to after the delivery of the report (including those with “complete confidence” going from 13 to 39 percent), only for this high confidence number to drop to 46 percent in the third survey. Democrats’ high confidence in Mueller decreased between the first two surveys, from 62 percent to 51 percent, and then it rebounded to 59 percent in the third survey. Independents’ high confidence was 44 percent in the pre-report poll, 49 percent after the Barr summary and 51 percent in the most recent survey.

While partisans have started to shift back toward their pre-report bases, with more Democrats than Republicans expressing high confidence in Mueller, results from this most recent survey are still far less polarized than the pre-report data. Pre-report, the share of Democrats with high confidence in Mueller was 43 points higher than the share of Republicans. In the second poll, immediately after the Barr summary, Republicans briefly led on share of respondents with high confidence in Mueller. In the third survey, again more Democrats than Republicans expressed high confidence in Mueller, but this margin was just 13 points. In both the first and third surveys, Independents and the overall population were squarely in between partisans on the left and right.

The next three questions covered confidence in Mueller’s investigative thoroughness and reporting on the following: potential misconduct by the Trump campaign or administration, links between the Russian government and Trump’s campaign, and any efforts to obstruct Mueller’s investigation.

High confidence in Mueller’s thoroughness in investigating misconduct by the Trump campaign or administration was at 47 percent pre-report; it increased to 55 percent after the Barr summary, and 58 percent in the third poll. Before the Mueller report was delivered, there was a 40-point gap between the share of Democrats (65 percent) and Republicans (25 percent) with high confidence in Mueller on this question. But after the third poll, Democrats, Republicans, Independents and, as a result, the overall population coalesced around high confidence in Mueller on this question in the 57–60 percent range.

High confidence in Mueller’s thoroughness in investigating links between the Russian government and the Trump campaign or administration largely mirrored the preceding question on general misconduct by Trump et al.

However, high confidence among Democrats and Independents in Mueller’s thoroughness in addressing efforts to obstruct his investigation diverged from the other confidence questions. Pre-report high confidence levels on this question paralleled the other confidence questions, but in the post-report poll, Democrats’ high confidence fell well below 50 percent and Independents’ high confidence did not budge. In the third poll, Democrats’ and Independents’ high confidence did increase, to 51 percent and 53 percent, respectively, but this is four to eight points lower than their high confidence in Mueller recorded for the other confidence questions.

A Plurality Now Believes Additional Investigation Is Needed

In addition to questions on the thoroughness and integrity of Mueller’s investigation, we also asked about the need for more investigation. Specifically, we asked:

The results show that the public does not consider this a closed case. In our pre-report poll, 40 percent expected no further investigation would be needed after the report was delivered, 31 percent believed additional investigation would be needed, while 29 percent did not know. In the post-report poll, this nine-point “no” margin for additional investigation shrank to four points; 38 percent said no, 34 percent said yes, while 28 percent did not know. But in the third poll, a plurality of 39 percent said “yes” additional investigation is needed, 38 percent said no, and 22 percent did not know.

The underlying results are deeply polarized. In the third poll, 66 percent of Republicans said no additional investigation is needed (13 percent said yes to additional investigation), just 16 percent of Democrats said no further investigation is needed (65 percent said yes to additional investigation), while Independents split at 38 percent for and against additional investigation.

The Public Is Split on Partisan Lines Over Whether Mueller’s Findings Are Damaging for Trump

In addition to questions on the thoroughness and integrity of Mueller’s investigation, we also asked about how damaging, if at all, Mueller’s findings are for Trump. Specifically, we asked:

While opinions over how damaging Mueller’s findings are for Trump may continue to evolve, the current perception is mixed and split along partisan lines. Using a scale that ranges from a score of 1, not at all damaging, to 5, highly damaging, 38 percent of the overall population rated Mueller’s findings as damaging for Trump (4 or 5), 41 percent indicated little or no damage (1 or 2), and 21 percent answered a neutral 3. But among Republicans, just 14 percent rated Mueller’s findings as damaging for Trump, 64 percent said little or no damage, and 22 percent were neutral. For Democrats, 59 percent said the findings were damaging, 20 percent said little or no damage, and 21 percent were neutral. Independents mirrored the overall population; 38 percent said damaging, 41 percent little or no damage, and 22 percent neutral.

The bottom line is that, across these three polls, Republicans’ confidence in the investigation increased dramatically, confidence among Democrats slipped and then inched up, and Independents’ confidence ticked up. But it should not be lost that a majority of Democrats retained high confidence in Mueller, and Independents are the least persuaded—either way—by evidence released in the report. The public’s initial take on the damage to Trump from Mueller’s findings is mixed, and there is a sharp divide on this on partisan lines. On further investigation, only Republicans view this as a closed case; a slim plurality of the overall population now believes additional investigation is needed.


From March 21 to March 22, March 26 to 28, and April 30 to May 2 we used Google Surveys, which is supporting this project with a large in-kind donation of access to its survey platform, to ask a variety of questions related to Mueller’s investigation. Respondents are internet users age 18 and older who answer “surveywall” questions on websites that use Google Opinion Rewards for Publishers to access content. Surveys appear on a network of more than 1,500 sites, including USA Today and the Financial Times. For more information on Google Surveys’ methodology, including questions regarding sampling bias and inferred demographics, please see Google’s white paper on the topic. Benjamin Wittes and Emma Kohse also discussed criticisms and advantages of the Google Surveys methodology at some length in this paper.