The National Republican Senatorial Committee raised more than $10 million in January, besting its Democratic counterpart as the Senate was adjudicating two articles of impeachment against President Trump.

The Democratic Senatorial Campaign Committee raised $8.5 million in the first month of the election year, finishing the period with $19.75 million in cash on hand. The NRSC's haul stemmed from robust online fundraising from grassroots donors that surpassed what the committee accumulated digitally during the first five months of 2018. The Senate GOP campaign arm had its best January ever and closed the month with a $25.2 million war chest to spend on the fall campaign.

The NRSC shared the figures with the Washington Examiner on Thursday.

Senate Republicans hold a slim three-seat majority, with incumbents particularly threatened by Democratic challengers in Arizona, Colorado, Iowa, Maine, and North Carolina. The Democrats are playing less defense, with incumbents in Alabama and Michigan vulnerable.

The DSCC typically raises more money than the NRSC. But this election cycle, Senate Republicans are outraising Senate Democrats. The GOP group is led by Chairman Todd Young of Indiana and overseen by Senate Majority Leader Mitch McConnell of Kentucky.