The initiative by the Congressional Leadership Fund, a super PAC aligned with Speaker Paul Ryan (R-Wis.), now includes 34 offices running mini-campaigns for vulnerable Republicans throughout the country. It has built its own in-house research and data teams and recruited 4,000 student volunteers, who have knocked on more than 10 million doors since February 2017.

The operation far eclipses the group’s activity in any previous election, when CLF didn’t have a single volunteer or field office. At this time last election cycle, the group had raised $2 million. As of Tuesday, CLF — which markets itself to donors as a super PAC dedicated to saving the House majority and can collect contributions with no dollar limit — had hauled in more than $71 million.

That war chest and new infrastructure could be a significant factor in an election year dominated by expectations of a Democratic wave fueled by a backlash against President Donald Trump.