With former Pennsylvania Senator Rick Santorum out of the primary, the dynamics of the presidential race have changed, with increased attention on the likelihood of a general election battle between Republican Mitt Romney and Democrat Barack Obama. In response, both campaigns have shifted into general election mode.

Monday, President Barack Obama launched an attack on Romney over transparency,

Calling on Romney to release his tax returns going back several years; disclose the top money "bundlers" to his campaign; detail his overseas investments; explain the deleted emails and missing hard drives from his time as governor of Massachusetts; and, thanks to reporters eavesdropping on a private fundraising event on Sunday, elaborate on why he told top donors that as president he would consider cutting federal agencies for education and housing.

Former Massachusetts Governor Mitt Romney, however, has his own plan of attack, and has begun attacking the President on issues ranging from healthcare, jobs, gas prices, and constitutional protections. At a Wisconsin rally on Friday, Romney faulted Obama for economic woes by claiming, "In Barack Obama’s government-centered society, the government must do more because the economy is doomed to do less. When you attack business and vilify success, you will have less business and less success." Speaking at the annual NRA meeting in St. Louis, he said: "We need a president who will stand up for the rights of hunters, sportsmen, and those seeking to protect their homes and their families. President Obama has not; I will."

And while the media has positioned Mitt Romney against Barack Obama as the general election competitors, Ron Paul is still a prominent force in the Republican Primary, unlikely to win the nomination, but determined to promote his ideology. Last weekend, he managed to pick up delegates in three congressional districts, adding 10 more delegates to his delegate count. Despite trailing Mitt Romney and Newt Gingrich, his campaign is still targeting the youth:

He’s long said that he wants to build a political movement as much as anything else, and if you look at his upcoming events, they remain heavy on appearances at colleges, which remain his most fertile ground for winning converts.

This week, he has scheduled events at the University of Rhode Island, Cornell, and University of Pittsburgh, capitalizing on his popularity among constituents aged 18-34.

But where is former House Speaker Newt Gingrich? Trying to dig himself out of a $4.5 million hole, he has resorted to desperate measures to keep his campaign alive. At the end of March, it was reported that Gingrich was charging supporters $50 for a photo with him, and now, in a risky move, has resorted to renting his donor list for as much as $26,000. Despite these measures, Newt Gingrich's campaign continues to plummet, partly due to his refusal to downgrade from private jets.

Do you think Newt Gingrich's debt will force him out of the race?