Democrats Doug Jones of Alabama and Tina Smith of Minnesota were sworn in Wednesday as the Senate's newest members, cutting the Republican majority in the chamber to a 51-49 margin.
Jones became the first Democratic senator in 25 years in the conservative state after defeating Republican Roy Moore last month in a special election. Moore, who faced multiple allegations of sexual misconduct and assault, campaigned against Jones to fill the seat vacated by Jeff Sessions, who now serves as attorney general.
Smith, the former lieutenant governor of Minnesota, was appointed by the governor to replace Al Franken, who resigned after being accused numerous times of sexual misconduct. With Smith's induction, there are now a record 22 women serving in the Senate.
By narrowing the Republican majority, the two senators could hinder Senate Republican leader Mitch McConnell's efforts to advance President Donald Trump's legislative agenda ahead of the November midterm elections.
But Jones has said he will resist the partisan bickering that has become increasingly common on Capitol Hill.
"I will be an independent voice and work to find common ground with my colleagues on both sides of the isle," he said after defeating Moore last month.
Smith is perceived by many to be a liberal Democrat who has cultivated ties to Minnesota's large and politically influential business community.