ALL SENATORS ARE EQUAL, BUT THEIR CLASSES AREN’T
Make no mistake — this year’s Senate elections are being waged on Republican turf. But that’s not uncommon. A third of all Senate seats are on the ballot every other November, which means that two-thirds of the Senate remains the same even after a federal election (special elections prompted by vacancies can create a bit more turnover). This is in stark contrast to the House, where every member is up for reelection every two years. The Senate “classes” predate the popular election of senators, which was enacted through the ratification of the 17th Amendment in 1913. As we’ve noted before, Democrats have to defend 21 Senate seats this cycle to the Republicans’ 14, and compounding their problems is that in the past four elections, the Democratic presidential candidate received an average of just 46.6% of the two-party presidential vote in the 33 states that have a Class 2 Senate seat, which are the ones up for election this year (the special elections coming up in Hawaii and South Carolina next year are not included because those seats are typically contested as part of different Senate classes). That’s the most Republican-tilting of the three Senate classes. Class 1, the Senate map