What bills could have passed in a Tea-Party-free America? For one, some kind of climate legislation to limit national greenhouse-gas emissions could have moved. One massive problem with the cap-and-trade bill that passed the House in June 2009 was that Democrats faced angry crowds at home when they defended it. That happened again and again on other issues, too, as Tea Partyers — talking to each other online, tuning in to Glenn Beck — would learn of some nightmare moving through Congress and turn their muskets on it. The in-person pressure, tactics they’d seen the left use for years, slowed down the Obama agenda…

Without the Tea Party, there still would have been some GOP primary challenges. In many ways, the new movement just amplified what the Club for Growth was already doing—making life impossible for Republicans who voted for tax increases. But Republicans weren’t proud to come from the Club; there’s nothing particularly populist about a tax-exempt 527 organization that vacuums up money from the private sector. Without the Tea Party, the 2010 Senate bids by Mike Lee (Utah) and Marco Rubio (Florida) would have been tougher. And just as important, the Republicans who didn’t face Tea Party challengers wouldn’t have looked in their rear-view mirrors.

The 2010 primaries—the wins and the threats—kept Republicans honest. In 1995, the GOP briefly fought a debt-limit vote but then balked. In 2011, there were rallies and new conservative power brokers demanding concessions in exchange for raising the debt limit. Without the Tea Party, Paul, Lee and Patrick J. Toomey (Pa.) wouldn’t have been in the Senate to give the debt standoff form and focus.

That is where this alternative history starts to look good to Republican leaders. The debt fight hit both parties, but it knocked the most out of the GOP. As the party has turned its attention to the presidential race, it has watched the man with the most endorsements—Mitt Romney—spar with pretenders, candidates who shouldn’t be competitive, given their fundraising and organizing limitations. Why is Herman Cain relevant? Because the Tea Party learned last year that it can demand the world—and nearly get it.