Here is a review of Marquette Law School polling from August 2019 to May 2020 in Wisconsin. All polls are state-wide samples of registered voters, with about 800 respondents per poll (1000 in Feb.) and a margin of error of about +/- 4 percentage points. Details of each survey and full methodology statement are available at https://law.marquette.edu/poll/category/results-and-data/

Biden v Trump

Biden Fav

Biden Fav, Dems only

Biden Fav, Dems Fav to Sanders

Biden Fav, Sanders Primary Voters

Trump Fav

Trump Job approval

Trump Coronavirus approval

Evers Coronavirus approval

Evers Job approval

Econ Last Year

Econ Next Year

Trump Economic approval

Race, sex and education

Race-sex-ed Mar-May only

Vote by region

Vote by region, March-May 2020

Vote by detailed region

Vote by urban-rural

Vote by age

Vote by attention to politics

Vote by likely to vote

Vote by liberal-conservative ideology

Vote by arty identification

Enthusiasm over time

I measure enthusiasm for voting in the November election, not for the particular candidate. I focus on those who say they are “very enthusiastic” to vote as the definition of enthusiasm.

Enthusiasm was quite high in January and February but dropped off in March and declined further in May. This may be due to the distracion of the coronavirus epidemic or some other reason.

Enthusiasm by poll, Jan. 2020-May 2020
Poll Dates Very Somewhat Not too Not at all n
1/8-12/20 70 22 5 3 800
2/19-23/20 73 18 3 5 1000
3/24-29/20 67 21 7 5 813
5/3-7/20 58 25 8 7 811

Enthusiasm by presidential vote choice

Enthusiasm by presidential vote choice combining all four polls finds no difference in enthusiasm for voting by candidate choice.

Enthusiasm by vote choice, Jan. 2020-May 2020
Vote choice Very Somewhat Not too Not at all n
Joe Biden 71 21 5 3 1620
Donald Trump 70 20 6 3 1532

Looking at monthly variation in enthusiasm shows that enthusiasm is equal for supporters of both candidates, and has declined equally in March and May from the high levels of January and February.

Enthusiasm by vote choice, January 8-12, 2020
Vote choice Very Somewhat Not too Not at all n
Joe Biden 72 22 3 2 388
Donald Trump 73 20 4 3 356
Enthusiasm by vote choice, February 19-23, 2020
Vote choice Very Somewhat Not too Not at all n
Joe Biden 76 18 3 3 464
Donald Trump 74 18 3 3 460
Enthusiasm by vote choice, March 24-29, 2020
Vote choice Very Somewhat Not too Not at all n
Joe Biden 69 20 6 4 392
Donald Trump 69 20 7 3 364
Enthusiasm by vote choice, May 3-7, 2020
Vote choice Very Somewhat Not too Not at all n
Joe Biden 64 24 6 5 376
Donald Trump 63 24 9 3 352

Enthusiasm by approval of Trump as president

Enthusiasm varies between those who approve strongly or only somewhat of the job Trump is doing as president, and similalry between those who disapprove strongly or somewhat.

Those who only somewhat approve or somewhat disapprove are markedly less enthusiastic about voting than those who strongly approve or strongly disapprove. A significant number of voters “somewhat approve” of Trump’s handling of his job, about twice as many as “somewhat disapprove.” Lower enthusiasm among this “somewhat approve” group could be a risk for Trump’s efforts to mobilize all his potential voters.

Among those with strong opinions of Trump’s performance as president, there is a small enthusiasm advantage among those who strongly approve over those who strongly disapprove, a potential weakness for the opposition to Trump.

Enthusiasm by Trump approval, Jan. 2020-May 2020
Trump approval Very Somewhat Not too Not at all n
Strongly approve 81 14 2 1 1143
Somewhat approve 35 42 13 8 497
Somewhat disapprove 44 35 9 10 228
Strongly disapprove 75 17 4 4 1434

Over the winter and spring of 2020 there has been variation in the enthusiasm gap between those who strongly approve of Trump and those who strongly disapprove. The gap was larger in January and especially in May, but was smaller in February and March.

This variation, and the combined data or all four months, supports the conclusion that Trump’s strongest supporters are a bit, by six percentage points or so, more enthusiastic about voting than are his strongest detractors, though this has varied modestly over time.

Enthusiasm by Trump approval, January 8-12, 2020
Trump approval Very Somewhat Not too Not at all n
Strongly approve 85 13 1 1 256
Somewhat approve 40 40 11 7 132
Somewhat disapprove 51 35 9 4 64
Strongly disapprove 76 19 4 1 324
Enthusiasm by Trump approval, February 19-23, 2020
Trump approval Very Somewhat Not too Not at all n
Strongly approve 84 11 3 1 358
Somewhat approve 38 43 5 12 125
Somewhat disapprove 49 33 6 8 55
Strongly disapprove 80 14 3 2 429
Enthusiasm by Trump approval, March 24-29, 2020
Trump approval Very Somewhat Not too Not at all n
Strongly approve 77 18 3 2 279
Somewhat approve 36 38 14 9 112
Somewhat disapprove 48 29 15 8 56
Strongly disapprove 74 15 6 5 339
Enthusiasm by Trump approval, May 3-7, 2020
Trump approval Very Somewhat Not too Not at all n
Strongly approve 78 17 3 1 250
Somewhat approve 26 46 23 4 129
Somewhat disapprove 26 45 7 21 53
Strongly disapprove 67 20 5 7 343

Enthusiasm by party identification

Enthusiasm varies across partisanship by strength of identification and by direction of party attachment.

The strongest partisans are the most enthusiastic, with Democrats holding a slight edge over Republicans. Enthusiasm drops as we move to independents who lean to a party and drops again for independents with no partisan lean. Those who lean Republican are slightly more enthusiastic than those who lean Democratic.

Enthusiasm by party identification, Jan. 2020-May 2020
Party ID Very Somewhat Not too Not at all n
Rep 71 21 5 3 1002
Lean Rep 66 20 8 5 553
Ind 48 24 9 13 289
Lean Dem 63 26 5 6 550
Dem 75 19 4 2 979

The net partisan edge, combining independents who lean to a party with full partisans is tiny.

Enthusiasm by party identification (including leaners as partisans), Jan. 2020-May 2020
Party w/leaners Very Somewhat Not too Not at all n
Republican 69 21 6 4 1555
Independent 48 24 9 13 289
Democrat 70 21 4 4 1528

Variation in enthusiasm by party from January through May has been modest.

Enthusiasm by Party w/leaners, January 8-12, 2020
Party w/leaners Very Somewhat Not too Not at all n
Republican 71 21 5 2 375
Independent 53 22 11 11 70
Democrat 73 22 3 1 341
Enthusiasm by Party w/leaners, February 19-23, 2020
Party w/leaners Very Somewhat Not too Not at all n
Republican 73 19 4 3 451
Independent 55 13 4 22 92
Democrat 78 18 2 2 443
Enthusiasm by Party w/leaners, March 24-29, 2020
Party w/leaners Very Somewhat Not too Not at all n
Republican 68 19 8 4 376
Independent 51 24 13 5 54
Democrat 68 22 5 5 378
Enthusiasm by Party w/leaners, May 3-7, 2020
Party w/leaners Very Somewhat Not too Not at all n
Republican 62 23 9 5 353
Independent 32 40 12 11 74
Democrat 62 24 6 8 367

There is little evidence to suport a clear enthusiasm advantage for either party.