NEW : Trump said he previously criticized Romney before getting to know him . The value of a Donald Trump endorsement of Mitt Romney is unclear . Rick Santorum agrees with Newt Gingrich that Florida delegates should be proportional . He says the GOP needs to unite behind one candidate, but not necessarily endorse someone who has been in politics for decades and whose name recognition may have faded over time.
NEW : Trump said he previously criticized Romney before getting to know him . The value of a Donald Trump endorsement of Mitt Romney is unclear . Rick Santorum agrees with Newt Gingrich that Florida delegates should be proportional . The Republican candidates are campaigning in Nevada , which holds its caucuses Saturday .