Democratic donors say it is “game on” following President Obama’s blessing of Democratic super-PACs designed to rip his GOP opponent to shreds.

The nod by Team Obama gave a clarion call of sorts to donors, who signaled on Tuesday that they would be more than happy to contribute to the top Democratic super-PAC, Priorities USA, which aims to turn the fight with expected GOP nominee Mitt Romney into a bloodbath.

“Game on,” one Obama donor said Tuesday. “If this is what it’s going to take, sign me up.”

{mosads}“Ideally, none of us like contributing to super-PACs, but I don’t see a choice in the matter and I’m glad we’ve decided to move forward on that” without the gray area, said another prominent Obama fundraiser. “We’ve been watching how much the other side is spending, and it’s been insane—and that’s just in a couple of weeks. I think Priorities will fill a much-needed gap.”

All the donors pointed to the recent cash flow on the GOP super-PAC side, with much of the money going to negative advertising. In Florida alone, during the recent primary, negative ads amounted to 92 percent of the total in the final week, according to Kantar’s Media Campaign Media Analysis Group.

And that’s just in a primary.

Both observers and donors alike expect an uptick in the fiery, negative, name-calling rhetoric between now and November, in what New York magazine recently dubbed “The Bloodiest Campaign Ever.”

“It’s going to be a tough, tough fight,” said Don Peebles, who serves on the Obama campaign’s national finance committee. “And in order to be competitive, the president is going to have to be supportive of super-PACs. It’s that simple. The landscape is pretty clear.

“The hardcore reality is that the campaign won’t be able to raise sufficient funds; they won’t be able to do it alone. The message I see is that it’s not going to be enough. They need the support of the super-PAC.”

Anthony Corrado, a professor of government at Colby College, said that while presidential campaign season was already shaping up to be a “highly competitive, hard-fought” race, the addition of super-PACs is “adding fuel to the fire.”

“This signal gives the ‘All Clear,’ ” Corrado said. “We can expect to see what will be a continuous negative advertising campaign between now and November.”

Obama and the Democratic National Committee (DNC) are expected to enjoy a fundraising edge over the GOP, but conservative independent super-PACs were expected to even the playing field. 

The decision to tell big-money donors to fund Democratic super-PACs signals that the Obama campaign — which with the DNC raised $233.7 million in 2011 — is “unwilling to cede any of its financial advantage,” according to Corrado. 

The move increases the likelihood of a $1 billion campaign and benefits Obama  “because it will leave the attack ads to the PAC,” he said.

Obama had previously kept Priorities USA — run by two former White House aides — at arm’s length and railed against super-PACs in general in speeches and appearances. Aides say he still opposes the Supreme Court’s 2010 Citizens United decision, which allowed unlimited and undisclosed funding into campaign politics and led to the advent of the super-PAC.

But Obama appeared to pivot toward the group earlier this week in an interview with NBC’s Matt Lauer. While Obama said in the interview that he would “love to take some of the big money out of politics,” he added: “Unfortunately, right now, partly because of Supreme Court rulings and a bunch of decisions out there, it is very hard to get your message out without having some resources.”

Republicans quickly criticized the decision, arguing the president had flipped his position. 

“Yet again, Barack Obama has proven he will literally do anything to win an election, including changing positions on the type of campaign spending he called nothing short of a ‘threat to our democracy,’ ” Joe Pounder, an official with the Republican National Committee, said in an email. “In less than 24 hours, Obama has gone from decrying super-PACs in the morning to opening up the door to their money during a conference call with his big-money donors in the middle of the night.”

Obama’s campaign on Tuesday sought to pre-empt that criticism by emphasizing that most donations to the president are small and hail from grassroots supporters. 

In an email to supporters on Monday night, Obama campaign manager Jim Messina said the super-PAC that supports Mitt Romney raised $30 million from fewer than 200 contributors. He said that 96 percent of what that group has spent to date — roughly $18 million — has been spent on attack ads.  

At the same time, Messina said, more than 1.3 million Americans have donated to the Obama campaign, with the average donation at $55 and 98 percent of donations coming in at $250 or less.

“If we fail to act, we concede this election to a small group of powerful people intent on removing the president at any cost,” Messina said.

The Obama campaign also suggested the GOP primary, in which Romney super-PACs have been effective in attacking Newt Gingrich, had been a factor. 

After observing the “intensity” and cash flow of the super-PACs on the Republican side in recent weeks, senior campaign officials said on Tuesday that they didn’t want to “unilaterally disarm.”

While the campaign officials said they wouldn’t characterize how Obama — who had been long opposed to super-PACs — came to the decision, they said the president  felt strongly that “we shouldn’t be going into this fight with one arm tied behind our back,” as one aide put it.

Donors said the super-PAC reflects the new political reality.

“The reality is when the facts on the ground change, you have to be able to adjust and change your strategy,” one donor said of the super-PAC decision.

“It’s an equalizer,” the fundraiser added.