Explainer-How could hardline US House Republicans strip Kevin McCarthy of his speakership?

As Republican U.S. House of Representatives Speaker Kevin McCarthy struggles to negotiate a deal to keep the government open, he faces a challenge from his right flank, with hardline members of his caucus threatening to oust him as their leader. The chamber's current rules allow any one member, Democrat or Republican, to introduce the motion. Republicans currently control the House with 221 seats to 212 Democrats, meaning if McCarthy wants to keep his speaker's gavel he cannot afford to lose more than four votes.