By the time voters went to the polls last week, outside groups had spent more than $454 million to influence campaigns. But there's little evidence that all that spending benefited Republicans much more than Democrats, as the final tallies on spending were actually pretty close.
A total of $197.4 million was spent backing Republican candidates, while groups spent $181.1 million for Democrats, according to Federal Election Commission data compiled by the Sunlight Foundation.
On both sides, the overwhelming majority of outside money was spent on negative ads. Of the total for Republicans, $155.9 million was spent on ads opposing Democratic candidates. Outside groups spent $144.8 million on ads opposing Republican candidates.
Democratic support was more likely to come through party committees like the Democratic Senatorial Campaign Committee. Republican support was more likely to come through outside groups like American Crossroads or Crossroads GPS—sister groups backed by conservative operatives (including Karl Rove). Those two groups alone spent $21.5 million and $16.7 million, respectively.
This was a record-setting year for outside spending, thanks in large part to the Supreme Court's Citizens United decision, which opened the floodgates for independent expenditures. But the money rushed in for both Republicans and Democrats.