Cortez Masto defeated Republican challenger Adam Laxalt, a former state attorney general who was endorsed by former President Donald Trump.
With Masto's victory on the heels of Democratic Senator Mark Kelly winning re-election in Arizona late on Friday, Democrats now control 50 Senate seats.
That is enough to cement Democrats' control of the Senate in 2023-24, as Democratic Vice President Kamala Harris can break ties in the 100-member chamber, securing victories for President Joe Biden.
If Democratic Senator Raphael Warnock were to win the Dec. 6 Georgia runoff election against Republican challenger Herschel Walker, that would expand Democrats' majority to 51-49. That, in turn, would give Democrats an additional edge in passing a limited number of controversial bills that are allowed to advance with a simple majority of votes, instead of the 60 needed for most legislation.
Currently, Democratic Senators Joe Manchin in West Virginia and Kyrsten Sinema in Arizona are "swing" votes who have blocked or delayed some of Biden's major initiatives, including expansions of some social programs.
But with 51 Democratic seats in the Congress that convenes next year, Manchin's and Sinema's influence could be slightly diluted.
