House and Senate races were a lot more interesting back when there were plenty of swing voters.

Whether they were “pure independents”—those who consider themselves independent and do not tilt in either direction—or whether they were soft partisans aligned with one party but who didn’t need much to jump to the other side, there are just a lot fewer of those people around anymore. There was a time when there were still conservative voters in the Democratic Party, often in small-town and rural America, and across the South. And there were also liberal voters among those who identified as Republican, particularly from New England and the rest of the Northeast, across the Midwestern industrial belt, and again on the West Coast.

Some states, such as Indiana, Kansas, Montana, North Carolina, North Dakota, Utah, Wisconsin, and Wyoming, would split their ticket more than others.

Seventy years ago, some complained that the two major political parties should be more ideologically coherent. It was as if the presence of conservatives in the Democratic Party and liberals in the Republican Party offended their sense of order and logic. In fact, the American Political Science Association even released a report in 1950, "Toward a More Responsible Two-Party System," recommending the two major parties be more ideologically distinct and internally cohesive.

Ironically, it was the presence of a two-party system, with two broad-based, ideologically and geographically diverse parties, with somewhat overlapping membership, that gave our system the stability it once had. Extremes were tempered: Divided government meant compromise, not stalemate. Former Senate Democratic Leader Tom Daschle has been known to say, “Compromise is not capitulation; compromise is the oxygen of democracy.” The system, as it was configured at the time, promoted those kinds of leaders and created that stability.

But that was then and this is now. One thing that has a remarkable influence on our election outcomes is that it isn’t just the two political parties that have sorted themselves, in terms of ideology and partisanship, but most states and districts have, too.

Whether you rank the 50 states by the 2024 share of the vote in each state for President Trump or by The Cook Political Report with Amy Walter’s “Partisan Voting Index,” there are few states and districts that aren’t either dependably Democratic or reliably Republican.

Most readers of this column can recite by heart the seven swing states: Arizona, Georgia, Michigan, Nevada, North Carolina, Pennsylvania, and Wisconsin. And then perhaps a second tier of a mixture of blue and purple, not comfortably in either group—we can call them the “burple” states of Minnesota, New Hampshire, New Jersey, Virginia, and New Mexico. And a pair of states we can call “rurple,” a mixture of red and purple, not quite red enough to forever be solid red, but certainly not yet purple—notably Florida and Texas.

Worth noting is that three out of the four Democratic Senate seats the GOP captured last year were in very red states: Ohio (Sherrod Brown), Montana (Jon Tester), and West Virginia (Joe Manchin), plus Dave McCormick unseating Democratic incumbent Bob Casey in Pennsylvania. Of the five purple states with Senate races, four stayed in the Democratic column, with incumbents Jacky Rosen in Nevada and Tammy Baldwin in Wisconsin getting reelected; then Democrats held onto open seats in Arizona and Michigan.

I looked through the 21 Senate races over the four election cycles from 2018 to 2024 in those seven purple states and found that Democrats had won 17 (81 percent) to Republicans' four (19 percent). Then I looked at the 44 Senate contests in those same seven races between 2000 and 2016, finding that Republicans had won 26 (59 percent) to 18 for Democrats (41 percent).

Since then, looking through the Senate races in states that were not among those seven, an interesting thing jumped out. To the extent that Senate Democrats were getting good fortune, it was edging out the narrative that Republicans were consolidating red states, one by one, picking off every Democratic seat in a red state. Today, there are no blue senators in red states.

Obviously last year’s Montana, Ohio, and West Virginia races were cases of that. But look back at 2018 when six seats flipped: four from Democrat to Republican and two from Republican to Democrat. The four GOP gains were all defeating Democratic incumbents in red states: in Florida, where Rick Scott unseated Bill Nelson, and in Indiana, with Mike Braun knocking off Joe Donnelly. There was Josh Hawley unseating Claire McCaskill in Missouri, while in North Dakota, Kevin Cramer successfully challenged Heidi Heitkamp. The two Democratic pickups that year were in purple states: the open seat in Arizona, where Kyrsten Sinema defeated appointed incumbent Martha McSally, and in Nevada, where Rosen defeated incumbent Dean Heller.

My theory is that Republicans are simply winning seats that they should have already had. But in these purple states, more often than not, Republicans are running suboptimal candidates—not all crazies and election deniers, but not so much blue-chip recruits. (Former Rep. Mike Rogers in Michigan is a notable exception).

A prominent GOP pollster confided to me last year that he was concerned that the kinds of Republicans the party used to be able to run in purple states and districts are reticent about running, fearful that while they might well be able to win a general election, they might not be able to win a primary in an increasingly MAGA-oriented GOP.

The challenge for Republicans is that there are no more Democrats occupying Senate seats in red states. In purple ones, sure. That includes Sens. Jon Ossoff and Raphael Warnock in Georgia, the former up next year, the latter in 2030; a Democratic pair in Arizona, with Mark Kelly up in 2028 and Ruben Gallego in 2030; and another pair in Nevada, Catherine Cortez Masto, next on the ballot in 2028, and the just-reelected Rosen, up in 2030. There’s also one in Michigan this year, where Gary Peters is retiring, and John Fetterman’s seat in Pennsylvania in 2028.

Interestingly, there is only one member of the Senate who stands in real contrast with her state: Republican Sen. Susan Collins of Maine, the only Republican holding a Senate seat in a blue state. All eyes will be on Gov. Janet Mills to see if she runs.

The moral of this story is that Republicans have now plucked all of the low-hanging fruit. They have already knocked off the last Democrats in red Senate seats. Now, they will need to get back to the era before 2018, when they did a better job matching the best candidates to win in purple states—not red candidates in purple states or so-so candidates in big-time critical races.

And here’s a moral for Democrats: Until your party becomes more credible in winning road games—that is to say, red-tilting areas that have disproportionately large rural votes, or just GOP-leaning voters in Florida who are drawn by low taxes—you will have a very difficult time winning and sustaining either a majority in the Senate or clearing the 270-vote threshold in the Electoral College with any regularity.

Charlie Cook Politics

The vanishing swing voter has made politics…