Security issues have tightened what is expected to be the most expensive Senate race in U.S. history.
Charles and David Koch each donated $2 million to a new super PAC through trusts in their names.
The RNC called the charge politically motivated.
Dismayed by the showing in 2012, contributors are dictating the timing and strategy of conservative groups, and much of the advertising is coming later than many on the right had hoped.
A final sum hasn’t been agreed upon, but one party official said it could be as much as $3 million each for the Democratic Congressional Campaign Committee and the Democratic Senatorial Campaign Committee, according to party officials familiar with the plans.
Critics say election commission’s opinion allows an end-run around the national party contribution limit.
The group is launching a $1 million anti-Braley TV campaign this week.
Americans for Prosperity plows millions into an operation that goes beyond the midterm elections.