Control of Congress is up for grabs as campaign season kicks into full swing in the coming weeks. The stakes for environmental and energy policy could be far-reaching.
Democrats need to flip just four seats to take the House majority, while Republicans would need just two to take the Senate.
The Senate is especially favorable to Republicans this year, as numerous Democrats will be fighting for wins in politically difficult states, including some where former President Donald Trump won the 2020 election.
The congressional primaries start Tuesday, with races including the closely watched Senate contest in California that will determine whether two Democrats or a Democrat and a Republican advance to the November general election there. Alabama, Arkansas, North Carolina and Texas will also hold their congressional primaries Tuesday.