Newt Gingrich and Mitt Romney are campaigning across Florida ahead of Tuesday's Republican presidential primary.
Gingrich is likening his call for establishing a colony on the moon to Abraham Lincoln's push to build a transcontinental railroad at a time when the technology didn't exist to do it. His says critics don't understand the power of science, technology and entrepreneurship to change the future.
Earlier this week, Romney said he'd fire any business executive who recommended spending huge sums on colonizing the moon.
The two candidates trailing Romney and Gingrich in the polls have left the state. Ron Paul is hosting a town hall this morning at the University of Southern Maine, while Rick Santorum is making a quick trip home to Pennsylvania, before hosting a fundraiser tonight in Washington, D.C.