More than a year before the midterm elections, the field team funded by a flush Republican super PAC has knocked on 1 million doors in districts Democrats are targeting in 2018.

The Congressional Leadership Fund, aligned with House Speaker Paul Ryan, R-Wis., shared with the Washington Examiner on Sunday that it surpassed the milestone over the weekend. The effort is a part of its effort to protect the most vulnerable Republicans, who could be on the ballot representing the party of a president with dangerously low job approval ratings.

So far this year, the super PAC also reached out to voters through more than 700,000 phone calls. The fund has focused on boosting Republicans in 13 districts.

"To win tough races, you must start early and have meaningful, ongoing conversations with voters on the issues they care most about. That's exactly what our field team is doing daily across the country," Corry Bliss, CLF's executive director, said in a statement.

The work includes voter turnout assistance for two Republicans who won special House elections: Rep. Greg Gianforte, in Montana's statewide at-large district, and Rep. Karen Handel in Georgia's Sixth Congressional District.

Other members receiving help are: Rep. Martha McSally, of Arizona; Reps. Jeff Denham, David Valadeo, Steve Knight and Ed Royce, all of California; Reps. Brian Mast and Carlos Curbelo, both of Florida; Rep. Erik Paulsen of Minnesota; Rep. Don Bacon of Nebraska; and Reps. Claudia Tenney and John Katko of New York.

CLF has budged $100 million for its 2018 campaign operation.

Bliss modeled CLF's field program after the program he ran for Sen. Rob Portman in 2016.

For that race, Bliss opened 15 field offices across Ohio and ended up knocking on more than 6 million doors. When he took the helm of CLF and decided to build a dedicated voter turnout operation, he hired some of his top field hands from the Portman campaign and began opening satellite offices.

The super PAC is currently operating a dozen field offices around the country, run by a full-time political operative. The field operation expects to expand to 30 offices around the country.

As he did for Portman in Ohio, Bliss is recruiting an army of high schoolers to serve as CLF volunteers.

They're put through a three-week training program — once they hit the ground, they're trained to talk about local issues that matter to voters in the area and the issues the incumbent Republicans that represent the district are focused on. However, there does appear to be one caveat condition for the CLF's support — supporting leadership's major initiatives.

Earlier this year, Bliss closed CLF's field office in Des Moines. It was opened to help Rep. David Young get re-elected. But, after he opposed the American Health Care Act, the House GOP bill to partially repeal Obamacare, CLF's Iowa office was shuttered.