Republicans currently hold a 53-47 majority, and Democrats would need to net three seats to win control of the chamber if they also win the White House — or four seats if Donald Trump wins reelection. The Senate map this year features far more Republican seats, but the vast majority are in states Trump won easily in 2016. Democrats are targeting only two states he lost four years ago, the same number of Trump-state Democratic incumbents up this year.
The most important states remain Arizona, Colorado, North Carolina and Maine, four races in which Democratic challengers outraised incumbent GOP senators in the first quarter of this year. These contests underscore just how costly the battle for the Senate will be: Super PACs in both parties have already reserved nearly $130 million for TV ads in these states, plus an emerging battleground in Iowa, to lay the foundation for the fall campaign.
Republicans have offensive targets in Alabama and Michigan, two seats that could help them preserve their control of the chamber even if they lose seats elsewhere. But Democrats have also recruited strong challengers in a string of red states that could come into play, including Montana, Kansas and a special election in Georgia, helping them potentially expand their path back to the majority.
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Republicans broadly acknowledge Democrats' massive financial edge, with early outside money flowing into every single battleground at a clip that dwarfs GOP spending. In Arizona, Colorado, Iowa, Maine, North Carolina and Kentucky, the GOP has already been outspent by millions from Democratic campaigns and outside groups. Democratic challengers outraised Republican incumbents in nine races, though Republicans maintain a cash advantages in all but two of them.
