(CNN) President Donald Trump declared political war on members of his own party Thursday morning in an unusual tweet that puts him at odds with members of Congress who share voters from the same ideological wing of the party.
In his tweet, Trump targeted members of the Freedom Caucus, a group of about three dozen conservative House members he said could "hurt the entire Republican agenda." Lumping them in with Democrats, Trump said in 2018, when the midterm election will be held, "we must fight them."
The Freedom Caucus finds itself in Trump's crosshairs after members of the group torpedoed Republicans' health care bill last week, refusing to vote "yes," and killing an early attempt to fulfill one of his campaign promises to repeal and replace Obamacare because many believed it did not go far enough.
During the Republican primary, Trump was viewed favorably by Republicans who self-identified as "conservative" and "very conservative," according to an October 2015 Gallup poll, the same ideological space occupied by the Freedom Caucus. According to a 2015 Pew study of 36 known members, the group is further to the right than the rest of House Republicans.
They were also more popular than Trump in November, winning by larger margins.
Comparing 2016 election results for 10 known members with data for how Trump fared in those same districts compiled from electiondata by Daily Kos found a pattern of Trump underperforming against the House members he's targeting.
While Trump has vowed to take on these members of Congress, the data suggests he could be in for a fight to convince conservative voters to dump conservative members of Congress they liked more than him.