Craig Gilbert

Milwaukee Journal Sentinel

There will be two big names on the Wisconsin ballot next year, and a few months ago both looked exceedingly vulnerable.

The state’s GOP governor, Scott Walker, was dogged by poor approval ratings throughout 2015 and 2016.

And the state’s Democratic U.S. senator, Tammy Baldwin, faced the specter of a GOP-friendly mid-term electorate in 2018.

But this year, the prospects have brightened for each incumbent.

Both saw their ratings improve last month in a poll by the Marquette University Law School. Both have seen potential front-line challengers take a pass on their race. It’s quite possible neither will draw a well-known opponent.

Each officeholder has vulnerabilities. Each race involves two huge unknowns: the identity of the challenger and the nature of the political climate next fall. This is not an attempt to handicap either contest.

But the possibility of Walker and Baldwin both winning seems more plausible today than it did last summer or fall.

It’s an intriguing scenario because it would defy a long-running trend.

It has been almost 20 years since Wisconsin had a split outcome at the top of the ticket (in which the state voted one way for the U.S. Senate and the other way for governor or president).

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The decline of ticket splitting, the rise of party-line voting and the growing impact of national politics on state races have diminished the odds of split outcomes.

The last time it happened in Wisconsin was 1998, when the state voted Democratic for U.S. Senator (Russ Feingold) and Republican for governor (Tommy Thompson).

Since then, Democrats swept races for Senate and president in 2000 and 2004, for Senate and governor in 2006, and for Senate and president in 2012. Republicans swept races for Senate and governor in 2010 and for Senate and president in 2016.

What are the ingredients for a split outcome in 2018?

Let’s start with the Senate race.

Baldwin’s numbers in the most recent Marquette poll (40% favorable, 35% unfavorable) are hardly ironclad. A large fraction of registered voters has no firm opinion of her. But this was one of her best ratings in recent years.

It seems likely that several Republicans will compete to oppose her, but it’s unclear whether any of them will be well known or have big-race experience.

One reason Baldwin looks less vulnerable now than she did a few months ago is her party’s presidential defeat last fall.

Had Democrat Hillary Clinton won, Baldwin would be facing a double whammy: a mid-term election cycle, in which turnout trends typically favor Republicans, and the potential drag of a Democratic president who entered office with high negatives and an unmatched capacity to inflame and mobilize conservative voters.

But with Donald Trump in the White House, the reverse may happen. Trump has suffered through the worst-ever approval ratings for a new president. He is doing poorly with independents right now, and he seems likely to inflame and mobilize Democratic voters next fall.

While Republicans have dominated recent mid-term elections in Wisconsin (2010 and 2014), those elections occurred under a Democratic president. The party of the president rarely prospers in mid-term races. The last good mid-term for Democrats was the last one under a GOP president. That was 2006, when Democrats won races in Wisconsin for governor and U.S. Senate and captured the state Senate.

Of course, the better the national climate is for Democrats such as Baldwin, the worse it is for Republicans such as Walker.

But Walker will be well-funded and well-organized, has three statewide wins under his belt and has no formidable opponents on the horizon.

His approval ratings are still negative, but they aren’t nearly as bad as they were for most of the last two years.

The governor averaged a “net approval” rating (approval minus disapproval) of minus 18 in 2015 and minus 13 in 2016, based on Marquette’s polling.

But in the Marquette survey released last month, his rating was minus three (45% approval, 48% disapprove). That’s far from great, but it was Walker’s best approval score since 2014.

The last time Wisconsin elected a governor and senator from different parties, in 1998, voting patterns were far less partisan than they are today. More than 20% of the state’s voters split their tickets for Senate and governor that year, according to exit polls.

By 2010, that figure had shrunk to 7%.

In Marquette’s most recent poll, only 7% of registered voters had a positive view of both Walker and Baldwin. The overlap in their support is likely to be small. And any national trends that boost one are likely to hurt the other.

But if their races are close enough, or if either or both of them fail to draw a strong challenger, then Wisconsin could break a near-20-year pattern and deliver a top-of-the-ticket victory to each political party.