Will Democrats take the Senate majority win November? That’s the big political question right now, and it makes sense to check in with one of the top analysts to see what he is thinking in his latest post, “The Races That Made the Senate Majority: A Three-Cycle Story” at The Center for Politics. As Kyle Kondik writes:

Because of the cyclical nature of the Senate, in which only a third or so of the body is contested every two years, it can be hard to get a handle on the races that truly “decided” the majority.

This is easier in the House, because all of the seats are on the ballot every two years, so one can just look at the closest races and determine how close (or not close) the minority party was from winning the majority. In 2024, Republicans won a 220-215 majority, and that included winning three races decided by about a point or less. Had those races gone the other way, Democrats would have won the majority. But Democrats actually did better in the closest races, winning four of the five races decided by less than 0.7 points. So it would not have taken much for Republicans to have won a bigger majority.

The Senate, ultimately, is similar: Had a few close-ish races gone differently over the last three election cycles, Democrats could conceivably hold the majority. However, Democrats have also been likelier to win the nailbiters than Republicans have, so one could also say that the GOP majority could be bigger than it is now.

This makes sense given the overall structure of the Senate. As we’ve discussed previously, 2024 represented a turning point in the Senate, as Republicans eliminated Democratic Senate representation from red states: Republicans now hold all 50 Senate seats in the 25 states Donald Trump won all three times he was on the ballot. Democrats hold 37 of the 38 in the 19 states that never voted for Trump: The lone exception is Sen. Susan Collins (R-ME), who has trailed leading opponent Graham Platner (D), although negative stories about the newcomer Platner mount. And Democrats hold 10 of the 12 seats in the six states that voted at least once for each party in the last three presidential elections (Arizona, Georgia, Michigan, Nevada, Pennsylvania, and Wisconsin).

Map 1 shows the current Senate breakdown. The bottom line is that there are just more red states than blue states, giving the Senate map an overall GOP skew even as Democrats have done well in the true battlegrounds.

What follows is a look at the 100 Senate seats, categorized by how each voted in its most recent election, either in 2020, 2022, or 2024. Some of these seats were on the ballot more than once over the last three cycles: For instance, Sens. Mark Kelly (D-AZ) and Raphael Warnock (D-GA) won special elections in the 2020 cycle and then regular elections in 2022, and both did better the second time than the first time (we used those more recent regular results in this analysis). If there was a runoff, as there was in both of Warnock’s victories, we used the runoff results.

More here.