The Senate's oddest of 'odd couples': In Tammy Baldwin and Ron Johnson, Wisconsin has produced a historically divergent pairing
This story was republished on Jan. 13, 2022 to make it free for all readers
In its four U.S. Senate elections since 2010, Wisconsin has twice elected a conservative Republican (Ron Johnson) and twice a liberal Democrat (Tammy Baldwin).
It turns out this is a very odd thing to do.
In a polarized age, Wisconsin is one of the few states left — just six — that have a senator from each side of the red-blue divide.
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It’s the lowest number of split Senate delegations in more than a century.
Of those six states (Wisconsin, Pennsylvania, Maine, West Virginia, Ohio and Montana), none have a pair of senators as far apart politically as Johnson and Baldwin.
That makes these two the oddest “odd couple” in the Senate.
They are not only an outlier in the current day, however.
They’re an outlier across decades of American politics.
In the modern history of the Senate, it is exceedingly rare for one of the chamber’s most liberal members and one of its most conservative members to represent the same state at the same time.
According to one rating system widely used by political scientists, Johnson and Baldwin are the most dissimilar pair of same-state senators of the past two decades. And it's hard to find true analogs in the decades before that.
Next year’s Senate election in Wisconsin — and Johnson’s decision about whether to run again in 2022 — will determine whether this unlikely pairing endures much longer.
But it has already lasted almost a decade, made possible by Wisconsin’s partisan parity and political swings, the effectiveness of the individual campaigns that Johnson and Baldwin have waged, the favorable political cycles they have run in, and a bit of happenstance.
Senate odd couples in history
Before exploring those factors, let’s take a closer look at the history of Senate odd couples and what makes this one so exceptional.
Forty years ago, there were 25 states with split Senate delegations.
Thirty years ago, there were 21 such states.
Twenty years ago, there were 14.
Ten years ago, there were 17.
Four years ago, there were 13.
Two years ago, there were 9.
Now there are six, the fewest number since 1914, the first year all senators were elected by popular vote.
The five other Senate pairs on this list are Democrat Sherrod Brown and Republican Rob Portman of Ohio; Democrat Joe Manchin and Republican Shelley Moore Capito of West Virginia; Independent Angus King (who caucuses with Democrats) and Republican Susan Collins of Maine; Democrat Bob Casey and Republican Pat Toomey of Pennsylvania; and Democrat Jon Tester and Republican Steve Daines of Montana.
These odd couples don’t all fit the same mold.
Two of these states are extremely balanced politically: Wisconsin and Pennsylvania.
Two are somewhat competitive but advantage one party: Ohio and Maine.
And two are lopsidedly Republican: Montana and West Virginia.
The other 44 states all have two senators from the same party that carried each of those states in the 2020 presidential election. This prevailing pattern reflects how state elections have become more and more nationalized along partisan lines. As fewer voters split their tickets or cross over to vote for candidates in the opposing party, more states and districts vote the same way for Congress as they do for president. And fewer states elect senators from both parties.
“With the polarization of our politics, there are fewer states in which you have truly competitive elections at the state level,” said political scientist David Canon, a congressional scholar at the University of Wisconsin-Madison. “And we’re also seeing a tighter connection between presidential results and Senate results.”
In 2016, every Senate race was won by the party that won that state for president. In 2020, that was true of all but one Senate race (Collins' victory in Maine).
The Senate’s six current odd couples differ from each in another respect.
In Maine and West Virginia, the Republican and Democratic senators are not that far apart politically — for members of opposing parties.
Collins and Capito are two of the least conservative Republicans in the Senate. King and Manchin are two of the least liberal Democrats. All four are in the political center of today’s 50-50 Senate.
The odd couples in Ohio, Pennsylvania and Montana are further apart. But they each feature at least one senator from the more moderate wings of their parties. Montana’s Tester is among the least liberal Democrats in the Senate. Pennsylvania’s Casey is in the moderate half of the Democratic caucus. And Ohio’s Portman is less conservative than most of his GOP colleagues.
That leaves Wisconsin as the only state with a Senate Democrat from that party’s liberal wing and a Senate Republican from that party’s conservative wing.
Rating senators on the right-left spectrum
How unusual is that in modern Senate history?
To answer that, I relied on a rating system widely used by political scientists. It places members of Congress on a right-left spectrum by measuring how similar or dissimilar their roll call votes are to those of their colleagues.
These ratings, known as DW-NOMINATE scores, offer two different ways to measure the political distance between senators.
First, these scores allow us to rank members in order, from 1 to 100, by how liberal or conservative they are within the body of the Senate.
Second, the system assigns a numerical value to lawmakers’ voting records. These are lifetime scores that make it possible to compare senators across time: conservative scores range from zero (the political midpoint) to plus 1, the maximum conservative score; liberal scores range from zero to minus 1, the maximum liberal score.
Currently, the most liberal senator is Massachusetts Democrat Elizabeth Warren, who has a lifetime score of -.763. The most conservative senator is first-year Alabama Republican Tommy Tuberville, who has a score of .936.
Everybody else sits between them politically. The Democrats closest to the middle are Manchin of West Virginia, Kyrsten Sinema of Arizona and King of Maine. The Republicans closest to the middle are Collins of Maine, Lisa Murkowski of Alaska and Capito of West Virginia.
If you follow the Senate, these rankings ring true. In fact, Manchin and Sinema are the two Democrats holding out against the desire of most of their colleagues in their party to get rid of the filibuster rule. Collins, Murkowski, Manchin and Tester are all part of the bipartisan Senate group that just announced an infrastructure deal with President Joe Biden.
Baldwin is currently rated as the sixth most liberal member of the Senate, after such colleagues as Warren, Bernie Sanders of Vermont and Corey Booker of New Jersey.
Johnson is rated as the 16th most conservative member, after such colleagues as Mike Lee of Utah, Rand Paul of Kentucky and Ted Cruz of Texas. Johnson used to rank in the top 10 among conservative senators, but more junior Republicans who’ve joined the Senate in recent years have been further to the right, pushing Johnson down the list.
Whether you use these ideological scores or their left-to-right rankings, Baldwin and Johnson are easily the Senate’s leading odd couple (as they are by other rating systems besides this one).
Using the rankings, there are 80 senators who currently sit between these two Wisconsinites on the ideological spectrum. By comparison, there are 60 members separating Pennsylvania’s two senators, 44 separating Ohio’s, 38 separating Montana’s, only three separating Maine’s, and three separating West Virginia’s.
The oddest pairing in decades
Using the scores, the gap between Baldwin’s and Johnson’s voting records is greater than that of any two same-state senators over the past two decades.
You have to go all the way back to the 1990s to find a truly comparable pairing: Minnesota Democrat Paul Wellstone, routinely rated as the most liberal member of the Senate, and the very conservative Minnesota Republican Rod Grams. The two served six years together, from January 1995 to January 2001.
To search for other analogs, I went back more than 70 years, thanks to a list provided by UCLA political scientist Jeffrey B. Lewis, the project leader for voteview.com, where all these congressional ratings can be found.
Since 1947, there is only one pair of same-state senators that had more divergent voting records than Baldwin and Johnson of Wisconsin and Wellstone and Grams of Minnesota: Democrat Glen Taylor and Republican Henry Dworshak, two Idaho senators who served together in the late 1940s.
This makes Baldwin and Johnson arguably one of the top three Senate odd couples of the 75-year post-war era.
Here are some examples of other odd couples that weren’t as far apart from each other as Johnson and Baldwin are: Democrat Gary Hart and Republican William Armstrong of Colorado in the 1970s and 1980s; Democrat John Edwards and Republican Jesse Helms of North Carolina in the 1990s and 2000s; Republican Everett Dirksen and Democrat Paul Douglas of Illinois in the 1950s and 1960s; and Republican Barry Goldwater and Democrat Dennis DeConcini of Arizona in the 1970s and 1980s.
The list also includes some previous Wisconsin pairings: Democrat Bill Proxmire and Republican Bob Kasten, who served together from 1981 to 1989, and Democrat Herb Kohl and Republican Johnson, who served together in 2011 and 2012. These are also among the odder odd couples of the past half-century.
The most enduring Senate odd couple of recent decades was Democrat Tom Harkin and Republican Charles Grassley of Iowa, who served together for 28 years. They were pretty far apart politically but not nearly as far apart as Baldwin and Johnson. In fact, as the GOP caucus has moved to the right over time, Grassley went from being more conservative than most Senate Republicans in the early 1980s to being less conservative than the vast majority of his GOP colleagues today.
There have been well over 100 distinct pairs of same-state senators from different parties serving together over the past four decades. But unlike some of the odd couples listed above, the vast majority have included at least one moderate. Many have included two, like Democrat Chuck Robb and Republican John Warner of Virginia in the 1990s, or Democrat Ben Nelson and Republican Chuck Hagel of Nebraska in the 2000s, or Collins and King of Maine today.
What, then, explains the enduring oddity of the Johnson-Baldwin pairing, now in its ninth year?
One contributing factor is Wisconsin’s 50/50 political divide. If a state favors Democrats, it might still elect a moderate Republican but probably not a conservative Republican. If a state favors Republicans, it might elect a moderate Democrat but probably not a liberal Democrat.
Yet small swings in a polarized, even-steven state such as Wisconsin make it possible to elect both liberal Democrats and conservative Republicans in alternating election cycles.
Pennsylvania is another highly competitive state, and its two senators, Casey and Toomey, are the most pronounced odd couple in the Senate after Johnson and Baldwin and one of the most dissimilar pairs of same-state senators in recent decades. (Toomey is retiring after this year).
In a more lopsided state like West Virginia, it requires a lot of ticket-splitting or crossover voting to produce a split Senate delegation. West Virginia voted for Republican Donald Trump by 42 points in 2016, so Democrat Manchin needed the support of lots and lots of Trump voters to get reelected in 2018.
The political dynamics in Wisconsin
In Wisconsin, however, it hasn't required a ton of crossover voting to send both Johnson and Baldwin to the Senate. It just required some modest political shifts from one cycle to another, and for both politicians to run effective campaigns (as Johnson did in 2010 and 2016 and Baldwin did in 2012 and 2018, when she won reelection by double-digits).
It has also mattered that both senators have enjoyed some good political fortune. Neither has had to run in a bad national environment for his or her party. Johnson won his first race in the GOP wave of 2010 and his second race in a year when Trump became the first Republican presidential candidate to carry Wisconsin since 1984.
Baldwin won her first race in 2012 with Democrat Barack Obama comfortably carrying the state at the top of the ticket. And she won her second race in the 2018 midterms when Democrats made gains nationally in Congress. There is an element of happenstance in the history of Senate odd couples.
But the long-term political forces appear very much against this dwindling phenomenon. The deck is stacked against split Senate delegations in states that lack the partisan parity of a Wisconsin or Pennsylvania. A few incumbents, such as Tester and Manchin, have been able to withstand the partisan tide in their states, but they could succumb in the future. After they retire (or lose) it will be much harder for their parties to compete there.
“I think this is going to be increasingly rare to have this kind of divergence between two (same-state) senators,” said UW's Canon.
Most Baldwin voters in Wisconsin would probably vote to replace Ron Johnson. And most Johnson voters would probably vote to replace Tammy Baldwin. These two senators cancel each other out on a lot of important votes.
But together they have made a strange kind of history as the longest-serving pair of polar political opposites in the modern history of the Senate.
Craig Gilbert is the Milwaukee Journal Sentinel’s Washington Bureau Chief and longtime political writer. Gilbert has covered every presidential campaign since 1988 and chronicled Wisconsin’s role as a swing state at the center of the nation’s political divide. He has written widely about polarization and voting trends, and won distinction for his data-driven analysis. Gilbert has served as a writer-in-residence at the University of Wisconsin-Madison, a Lubar Fellow at Marquette Law School and a Knight-Wallace Fellow at the University of Michigan, where he studied public opinion, survey research, voting behavior and statistics.
Email him at [email protected]; follow him on Twitter: @Wisvoter.
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This article originally appeared on Milwaukee Journal Sentinel: Wisconsin's Ron Johnson and Tammy Baldwin: the Senate's oddest couple
