Leaders of Priorities USA Action, the Democratic super PAC mobilizing for the 2016 White House race, are urging the group’s donors to devote their resources in the coming year to two congressional super PACS, underscoring the close alignment between the super PACs on the left.

In a memo sent to top contributors Monday, Priorities USA Executive Director Buffy Wicks declared: “No one should sit out the 2014 midterm elections, period.”

“The first battleground of the 2016 presidential campaign is the 2014 mid-term elections,” Wicks wrote in a letter obtained by The Washington Post. She urged Priorities donors to give to House Majority PAC and Senate Majority PAC, the two super PACs providing air cover for congressional Democrats.

“If you have yet to give, please understand how high the stakes are and donate,” she wrote. “The next Democratic President will have a much easier time if she – or he – has a Democratic House and Senate.”

The missive sought to dispel confusion about the role that Priorities will play in the coming year. The super PAC, which has recently configured itself as the big money vehicle that will support Hillary Rodham Clinton if she makes another run for the White House, is not going to actively solicit donations this year. “We have strongly encouraged donors to support midterm efforts and won’t aggressively raise for 2016 until after the midterm cycle,” Wicks wrote.

That decision comes amid building anxiety in Democratic circles about whether there will be ample financial resources available in 2014 to compete with the tens of millions of dollars being spent by Americans for Prosperity, the conservative advocacy group backed by billionaire industrialists Charles and David Koch.

In her memo Monday, Wicks wrote that Priorities is “playing a vital role in supporting Democrats in the 2014 elections.” The group donated $250,000 apiece to House Majority and Senate Majority, and its board members and strategists are volunteering their efforts in key races.

“Almost as important as what we are doing is what we are not doing,” she wrote. “We are not competing with the House and Senate Super PACs. We are not reinventing the wheel. We are not duplicating efforts.”

“We will not big-foot them or siphon resources from them,” she added. “Instead, we will do all we can to help and support them.”