The rules of the House Freedom Caucus require 80% of their members to agree on it before the organization itself makes an endorsement. There are 42 known members of the HFC (it's impossible to know their full member count because they do the whole Fight Club thing). This means at least 34 GOP Congressmen aren't voting for McCarthy. If they maintain their opposition through the actual Speaker election, it would keep McCarthy below 218 votes and prevent his election. There's no reason to believe they wouldn't actually do this, which means they have the leverage to demand major concessions from the Republican leadership. McCarthy must either pay their ransom in order to become Speaker, or call their bluff and risk a major embarrassment to both himself and the party.
This is what it feels like to be on the other side of obstructionism 
If they hold the vote and no one gets 218 votes, what happens?
