U.S. House Speaker John Boehner, R-Ohio, announced Friday he will resign from Congress at the end of October 2015. Reuters/Yuri Gripas

The tea party wave that gave John Boehner his gavel four years ago has now cost him his job. With the Republican speaker’s sudden announcement Friday that he will step down, the party has officially lost control of its conservative base.

In recent weeks, Boehner has tried to beat back coup attempts by conservative lawmakers who want to shut down the federal government unless Congress votes to defund women’s healthcare provider Planned Parenthood -- a nonstarter with Democrats and the president. On Friday, Boehner gave in, announcing he will resign at the end of October.

Boehner ascended to the speakership after the 2010 midterm elections. That year, the GOP won dozens of congressional seats and flipped the House of Representatives, as the party embraced the conservative tea party movement. Five years later, the House’s conservatives no longer need Boehner or the Republican Party’s support. That’s because they can count on support from outside spending groups, and represent districts drawn to be conservative constituencies.

With the rise of super PACs and outside spending groups that can raise and spend unlimited money on elections, new congressmen and candidates don’t have to rely as much on the leadership for fundraising help. While outside groups are supposed to operate independently from candidates, many members of Congress have seen their supporters set up super PACs to back their campaigns, boosted by money raised without contribution limits from wealthy donors, thanks to the Supreme Court's 2010 Citizens United decision.

Conservative Republican congressmen and candidates have also received substantial support in recent years from ideological groups like the Club for Growth and Americans for Prosperity, the latter of which has been funded by billionaire businessmen Charles and David Koch and their vast donor network.

For the most part, conservative lawmakers don’t have to worry about losing their seats after getting elected either. In 2012, Democratic congressional candidates received more votes nationally than Republicans, yet the GOP managed to gain seats in the House. Thanks in part to GOP-led redistricting processes in the states and shifts in populations, the Republican Party has a formidable structural advantage, and its members mostly hold safe seats and represent conservative constituents.