Obama team: If Romney can't stand up to Limbaugh, how will he stand up to Ahmadinejad?

(CBS News) President Obama's re-election team acknowledged on Wednesday that it'd be easier to rally supporters against one Republican candidate. On the other hand, they said, the extended GOP primary is bringing out the worst in the president's potential rivals.

"I think every single day people watch these candidates their sense of urgency grows about the need to re-elect the president," Obama political adviser David Axelrod told reporters on a conference call the day after Super Tuesday. The Republicans, he said, have been in a "mad scramble to respond to the most strident voices in their party."

Axelrod said the controversy over conservative radio host Rush Limbaugh's offensive remarks against student activist Sandra Fluke was a "test of leadership" that Mitt Romney in particular failed by not strongly rebuking the remarks.

"The Limbaugh thing was test of leadership, and you have them all the time, and Mitt Romney's failed them in this campaign," he said. "If you don't have the strength to stand up to the most strident voices of your party, how are you doing to stand up to Ahmadinejad?"

Mr. Obama's re-election team is eager to confront Romney over that and a host of other issues, presuming he'll be the nominee -- but the problem is, he's not the nominee yet.

Obama campaign manager Jim Messina emailed the president's supporters in the middle of the night following the 10 Super Tuesday contests. The primary results gave Rick Santorum and Newt Gingrich enough staying power to be a problem for Romney, if not win the nomination.

"Ten states voted in the Republican primary tonight -- now 23 in all -- and we still don't have an opponent," Messina wrote. "Here's the problem with that: Too many Obama supporters are waiting until there's a clear Republican nominee to make their first donation. That kind of thinking loses elections."

Axelrod acknowledged Wednesday, "I do think it's easier to raise money when you have one opponent."

Messina told reporters that the Obama campaign has to be prepared for over half a billion in campaign spending from super PACs.

"We are in a whole new world here," Axelrod said.

But while fundraising may be a concern, the Obama team says the prolonged Republican primary is giving them time to build a strong on-the-ground organization in key states. The Obama campaign registered over 3,000 voters in North Carolina over the weekend, where Mr. Obama is visiting today, Messina said, as well as 2,000 in Virginia.

"While they're destroying each other, we're building a campaign nationally based on a positive vision for this nation," Axelrod said. "If you're looking at where we were six months ago, we're making steady progress because of what we're doing, what the economy's doing and because of what the Republicans are doing."

The campaign also said they're doing better in states like Ohio than they were six months ago, and expanding Mr. Obama's potential map, citing states like Arizona.