A fundraising solicitation sent by Ron Paul on Wednesday painted a frank picture of the future of his campaign: Donate now, or he might have to call it quits.

Paul has retreated from the public spotlight in recent weeks as Mitt Romney's hold over the Republican presidential nomination has grown tighter and tighter. He has scaled back his campaign-trail appearances and television interviews.

ADVERTISEMENT

But unlike Rick Santorum, who dropped out of the race on Tuesday, Paul has given few previous indications that he could bow out.

"I won't mince words," Paul said in an email to supporters Wednesday evening. "If we don't reach our $2.5 million goal, I am not sure our campaign can go on."

Paul said the goal of the money bomb is to reach $2.5 million by Tax Day, on April 15, as part of his push for "taxpayer freedom." He said that although political elites have declared the race over, he had little intention of acquiescing and hoped to fight on.

"In the coming days, the media will be expecting me to also bow down to their new prince," he wrote. "Well, I want to give them a little surprise. Instead of a defeated candidate bowing out of the race, as we saw yesterday, let's show them a surging candidate determined to ride on to Tampa!"

Newt Gingrich, the other remaining Republican in the primary race, also emailed supporters announcing a goal of 12,000 donations by midnight on Wednesday. That email came amid reports that Gingrich's campaign debt is mounting and that a $500 check his campaign wrote to the State of Utah for a ballot filing fee had bounced.

But Gingrich gave no indications in his email that his continued presence in the race depended on a fast infusion of cash.

"I am committed to being the voice for our shared conservative values all the way to the Convention in Tampa," Gingrich said.