It's the Republicans (duh), by a staggering 81%.
The top-line numbers: Through Nov. 1, at least $213 million had been spent on the presidential, Senate, and congressional races by groups that do not disclose their donors. Of that total, $172.4 million (81 percent) was spent to support Republican candidates, while $35.7 million (19 percent) was spent to support Democratic candidates.
While 110 dark money groups have spent money on the election this year, the real money is being spent by just a handful of groups. The top five groups, all Republican-supporting, account for 64 percent of dark money spending. In fact, just two groups, Crossroads GPS and the U.S. Chamber of Commerce, account for 46 percent of the spending all by themselves.
And these numbers may only be a partial picture, because groups that don’t disclose their donors also don’t have to disclose their spending until a few weeks before an election.
Thanks, Citizens United! What an ugly mantra that's become.