If this primary season has taught the GOP anything, it's that winning a civil war is expensive. The establishment has managed to stave off most of its Tea Party challengers, but at a cost of tens of millions of dollars months before the midterm elections. Meanwhile conservatives groups have spent nearly as much to win more influence than actual primaries.
According to Politico's review of FEC filings, pro-establishment groups have spent $23 million on independent expenditures helping candidates in about 20 House and Senate races. Tea party groups like Club for Growth, Senate Conservatives Fund, FreedomWorks and Tea Party Patriots have spent an additional $12.5 million, though they have fewer candidates to show for it. To put that into context: In 2012, Republican nominees spent about $23 million total on the three most competitive Senate races — North Dakota, Indiana and Nevada — but against Democrats. Or, put another way, according to the Center for Responsive Politics, independent expenditures from non-party committees were only at $24.8 million on this day in 2010, and that's including left-leaning groups.
So what does the Republican party have to show for all that spending? With the exception of Rep. Eric Cantor, the Establishment has advanced most of the candidates it wanted. Conservative groups like the Club for Growth, however, have invested millions in candidates who didn't make it. Most recently, the group spent $3.1 million on Chris McDaniel's campaign to replace Sen. Thad Cochran as the nominee in Mississippi, including $600,000 during the three week runoff period, according to The Washington Post.