Story highlights The long struggle to save Obama's Affordable Care Act has invigorated liberal activists

Organizers say they have already enlisted more than 4,000 volunteers dedicated to building a new activist network

(CNN) As President Donald Trump's policies and rhetoric have put him increasingly at odds with the national Republican party, a leading progressive organization is kicking off a new grassroots campaign to link vulnerable GOP House members to Trump's troubled brand.

Organizing for Action, the group spawned by former President Barack Obama's national campaigns, is beginning the program by focusing on 34 seats in GOP-held congressional districts around the country where Trump received less than 50% of the vote last November.

Sixteen months out from the 2018 midterm elections, organizers say they have already enlisted more than 4,000 volunteers dedicated to building a new activist network. OFA's plan is to enlist and train a small army of hometown organizers to agitate against endangered lawmakers like Rep. Carlos Curbelo of Florida and California Rep. Darrell Issa. Both congressmen voted to pass an unpopular Obamacare repeal bill in the House and are expected to face tough re-election bids next year.

Volunteers, many new to tedious arts of effective phone banking and canvassing, will receive training through the organization. Their energies will then be directed at recruiting friends and neighbors, and building capacity in an effort to pin down the nearly three dozen lawmakers highlighted on an OFA-designed website called "Rubber Stamp Reps." If the designation sticks, they hope it will prove especially damaging in districts where Trump was a divisive figure even before his post-inauguration plummet in the polls.

Arizona Sen. Jeff Flake, a longtime Trump-skeptical Republican who has ramped up his criticism of the President with the release of a new book, recently offered the initiative a tailor-made talking point when he called out his colleagues for going along too easily with the administration's wishes.

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