Catherine Cortez Masto’s victory in Nevada clinched the chamber for Democrats.
The 2022 midterm elections shaped up to be some of the most consequential in the nation's recent history, with control of Congress at stake.
All 435 seats in the House and 35 of 100 seats in the Senate were on the ballot, as well as several influential gubernatorial elections in battleground states like Arizona, Georgia, Pennsylvania and Wisconsin.
Democrats were defending their narrow majorities in both chambers and retained control of the Senate, though control of the House isn't yet clear. But a Republican flip of the lower chamber would be enough to curtail most of President Joe Biden's legislative agenda and would likely result in investigations against his administration and even his family.
ABC News can project that Republican John Kennedy will win a third term to the U.S. Senate. Kennedy faced a number of challengers, including Democrats Luke Mixon and Gary Chambers Jr.
In Louisiana, all candidates regardless of party affiliation compete in a first-round election, in which a candidate can win by receiving more than 50% of the vote.
Polls have now closed in Montana, Nevada, Pennsylvania and Utah. Polls typically close at 8 p.m. statewide in Pennsylvania, though polling location hours were extended to 10 p.m. in Luzerne County after the county reported delays with voting due to paper shortages.
ABC News can project that Republican Gov. Kristi Noem will win her bid for reelection in South Dakota against Democratic challenger Jamie Smith.
ABC News can project that Democratic incumbent Michael Bennet will win Colorado's Senate race against Republican nominee Joe O'Dea.
"This was a moderate Republican trying to win in a state that has become increasingly more Democratic," ABC chief Washington correspondent Jonathan Karl said of O'Dea on ABC News Live.
O'Dea was "very critical" of former President Donald Trump, "and Donald Trump right back at him," Karl said. "In fact, [Florida Gov.] Ron DeSantis endorsed Joe O'Dea just a few days ago and Trump criticized [DeSantis], saying it was a big mistake."
