Washington (CNN) The most conservative congressmen in the country were a major roadblock in President Donald Trump's first push to replace Obamacare. Now, a second attempt's fate is in the hands of a moderate Republican faction -- putting to the test the power of Democratic resistance.

Progressives have protested at those Republicans' town halls, marched through major cities and filled lawmakers' voicemails.

If they've convinced those lawmakers in swing districts their passion is real -- and could cost them their seats in the 2018 midterms -- it could translate into a long-term Democratic victory over conservatives in setting the nation's health care policy.

As President Donald Trump makes another push to repeal Obamacare around the 100-day mark of his tenure in office, House Speaker Paul Ryan and Republicans appear to have solved their problems with hardline conservatives but haven't yet rounded up enough support from moderates to give Trump the 216 votes he needs.

Already, the White House's hopes of a vote this week were dashed, with mostly moderate Republicans either opposing the measure or refusing to take a public position and Ryan saying he won't move forward with a bill that's at risk of being defeated on the House floor.

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