It's a similar story in other states. McConnell's rout cost him $10 million and exposed his weakness with his party's base. In Oregon, pediatric neurosurgeon Monica Wehby, hailed as the candidate who could turn a blue state red, had to first survive a primary opponent who decried her moderate views on abortion, gay marriage, and healthcare. (Wehby may have been more damaged by late-breaking revelations about her personal life, which her Republican opponent says he did not dig up.) In Idaho, the attempt to take out Simpson fizzled early—the Club for Growth took its ads down weeks ago, tacitly conceding its challenge was doomed—but only after an all-out, $4 million push by Simpson and his allies, including the Chamber of Commerce and the Defending Main Street Super PAC.

Multiway primaries for open seats happened before the Tea Party came along, of course—ambitious politicians will always jockey for the next rung on the political ladder. Democrats even have them now and then, as they did in Pennsylvania on Tuesday, where a wealthy businessman, Tom Wolf, swooped in and snatched the gubernatorial nomination from the congresswoman, Allyson Schwartz, who thought it was hers for the taking. Many of the GOP primaries that have been shoehorned into the establishment-versus-Tea Party narrative in recent years weren't that at all, as Dave Weigel helpfully reminds us.

Yet Republican infighting is far more common and more brutal than that experienced by Democrats, egged on by a constellation of rabble-rousing conservative groups who pour money into ginning up the base. These battles, it hardly needs to be said, inevitably push the nominee to the right in ways that may alienate moderate voters. North Carolina's Republican Senate nominee, Thom Tillis, sought to reassure primary voters of his anti-Obamacare bona fides by boasting about how he worked to prevent the state from expanding Medicaid; now his Democratic opponent, Senator Kay Hagan, is attacking him for his opposition to the expansion, which is generally popular.

When McConnell's victory was declared on Tuesday night, national conservative groups rushed to embrace McConnell. The Senate Conservatives Fund, the Madison Project, FreedomWorks, and the Tea Party Patriots all issued statements calling for unity. (Only Bevin was not on board; embittered by his rough treatment at the hands of a wily political operator, he complained about having been "lied about" and "ridiculed.") But the question remains whether the groups will throw themselves into the effort to reelect McConnell with as much gusto as they devoted to trying to take him down. For many on the right, attacking Republicans has become the only thing they know how to do.

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