The House Majority PAC raised $5.2 million in the first quarter, three times what it raised during the same period in 2012, the group announced Wednesday morning.

"This impressive fundraising total shows that Democratic donors are committed to combatting the millions the Koch Brothers are spending in an attempt to buy the House of Representatives," said House Majority PAC Executive Director Alixandria Lapp. "We are making wise investments in races across the board where we can make a real difference."

The group has now pulled in $12.7 million for the cycle. It didn't announce how much cash it has in the bank, but it has been spending big on early ads to protect vulnerable members like Rep. Nick RahallNick Joe RahallWe shouldn't allow politics to impede disaster relief Break the cycle of partisanship with infant, child health care programs Clinton mulls role in 2018 midterms MORE (D-W.Va.).

With Americans for Prosperity and other GOP groups spending big on early advertising, the House Majority PAC is Democrats' best hope of responding to those ads so that members can reserve their own resources for TV ads in the fall.