Craig Gilbert

Milwaukee Journal Sentinel

In some elections, the most interesting places to watch are not the swingy “purple” ones but the lopsided “red” and “blue” ones.

This is one of those elections.

And Waukesha and Dane counties are two of those places.

Because they are polar opposites politically, they offer a window into one of the keys to the 2016 presidential election.

Who’s winning the battle of the bases — Hillary Clinton or Donald Trump?

Which candidate is doing a better job unifying the voters in his or her party?

The polling in Wisconsin right now suggests that it is Clinton, although that comes with some caveats. Both candidates are struggling to excite the party faithful. More voters than usual are on the fence.

But Trump is struggling more than Clinton, and Waukesha and Dane are striking cases in point.

Clinton has carved out the kind of massive lead in Dane County you’d expect from a Democratic nominee. Yet Trump has failed to dominate in Waukesha, a county he lost by nearly 40 points in the state’s April primary.

Elections are won and lost by not just the battle over swing voters, but the loyalty and turnout of partisan Democrats and Republicans. The reddest and bluest counties in battleground states like Wisconsin will leave their stamp on this contest.

Here is a closer look at how Trump and Clinton are faring in two classic “base” counties — liberal Dane, home of the state’s capital and flagship university; and conservative Waukesha on the suburban outskirts of Milwaukee. The polling data was provided by Marquette University Law School pollster Charles Franklin, who combined four separate Wisconsin surveys from June to late August to get a meaningful sample of voters from each county:

Head to head. Trump’s lead over Clinton in Waukesha County this summer was just 13 points (45% to 32%) — an undersized margin in a county the GOP typically wins by 30 or 40 points.

Clinton’s lead over Trump in Dane County was 44 points (62% to 18%) — which matches President Barack Obama’s 44-point margin over Republican Mitt Romney four years ago.

Popularity. Trump’s image in Waukesha is very negative for a GOP nominee: 33% view him favorably, 59% unfavorably. His favorability rating is 16 points lower than Romney’s was in Waukesha. (Trump’s struggles in this ultra-red county were the subject of a lengthy Milwaukee Journal Sentinel analysis last week).

Clinton’s standing in Dane is nothing to brag about. She is viewed favorably by 53% of registered voters and unfavorably by 41% — very mediocre numbers for the state’s most Democratic county. Her favorability rating is 16 points lower than Obama’s in Dane. But her image is still more positive than negative, which can’t be said of Trump in Waukesha.

President vs. Senate. Trump has been running about 15 points behind his party’s Senate candidate, Ron Johnson, in Waukesha. (Trump’s lead over Clinton was 45% to 32%; Johnson’s lead over Democrat Russ Feingold was 60% to 33%).

Clinton isn’t facing the same problem in Dane. Her lead over Trump this summer in Dane County was 62% to 18%. Feingold’s lead over Johnson was 67% to 25%.

In ultra-red Waukesha, presidential choice gives voters the blues

Both Trump and Clinton are less popular than their party’s Senate candidates in these base counties. Trump’s favorability rating is 14 points lower than Johnson’s in Waukesha. Clinton’s favorability rating is 11 points lower than Feingold’s in Dane.

But Clinton has matched Feingold’s lead in Dane County despite that difference.

One big reason is Trump’s extreme unpopularity in Dane, where he is viewed favorably by just 14% of registered voters and unfavorably by 80%.

In fact, Trump is so unpopular there that he has been running third in Dane County this summer — slightly behind Libertarian Gary Johnson — when third-party candidates are included in the polling. In a four-way choice, Dane County voters broke down this way in Marquette’s summer surveys: Clinton 55%, Gary Johnson 17.5%, Trump 15.6%, Green Party candidate Jill Stein 6%.

The undecided. There is a large pool of uncommitted voters in both Waukesha and Dane. In both counties, about one in five voters are withholding their support from the two major-party presidential candidates.

That group grows to almost one in three when voters are offered third-party candidates Johnson and Stein as options.

This could signal a dip in turnout from four years ago in both base counties, and turnout in these areas will be critical for each side. Meanwhile, the size of the undecided vote underscores Trump’s struggles in Waukesha. His failure to unify the GOP base has kept him below 50% in a county where a strong GOP nominee should win 65% or 70% of the vote.

Base vs. base. Dane and Waukesha are only part of the story in Wisconsin. In some other parts of the state — especially northern Wisconsin and the Green Bay region — Trump is doing better than Mitt Romney did four years ago, not worse.

Things can also change in Dane and Waukesha. Trump’s struggles this spring and summer in the conservative suburbs of southeastern Wisconsin could be viewed as an opportunity for the Republican nominee. Trump has only been winning about 80% of the GOP vote in Wisconsin, while Clinton has been carrying about 90% of the Democratic vote. If reluctant Republicans “come home” this fall — as they often do — Trump can close the gap in a state where he has consistently trailed in the polls, and where he cut into Clinton's lead in recent polls.

But Dane and Waukesha also represent real danger signs for Trump. They are the second and third biggest counties in the state. They’re hotbeds of political engagement. In 2012, they ranked in the top five in turnout among U.S. counties with more than 50,000 people. They normally provide huge vote margins for their dominant parties, making their performance this fall crucial if the race for president is a close one.

Trump has been underperforming in both. Clinton appears poised to win big in the state’s major Democratic strongholds of Dane County and the city of Milwaukee, where she leads Trump by almost 60 points. But Trump’s margins in the GOP suburban heartland in and around Waukesha are in question.

If Trump loses the battle of the bases, he will have to put up remarkable numbers in the more purple parts of the state to have a shot at winning Wisconsin.