Rush Limbaugh on Monday urged his listeners in Ohio to vote for Donald Trump over Gov. John Kasich in the state's Tuesday primary."My preference is that Trump win Florida and Ohio," Limbaugh said."Have you heard what Kasich did today?" he continued."I'm gonna tell you what's happening here, folks. Kasich has come out full-throated, 100 percent for amnesty. He is talking like Jeb Bush talks about amnesty and the illegal immigrants as gifts from God or some such thing."Rush said the only way to clear the field, and allow Cruz to emerge as the real conservative challenger to Trump, is for Rubio and Kasich to lose and quit the race."What's going on here, the establishment has one last great hope, and that's Kasich winning in Ohio," he said."But if [Kasich’s] elected president within the first hundred days we're gonna get comprehensive immigration reform, amnesty," Rush said.Limbaugh noted that only Cruz can still beat Trump."Now, even if Kasich wins Ohio, he's mathematically eliminated from winning the nomination in the primaries," Limbaugh said. "He cannot get the 1,237 even if he wins Ohio. If he loses it, it's not even close."Limbaugh has previously praised Ted Cruz."Ted Cruz is only guy that was taking on the Republican establishment of all the Republicans in the race," Limbaugh told his 10 million listeners in February."And he was the only guy who had been fighting the establishment and he had done it to their face."He was such an outsider that even as a member of the Senate he was hated, despised, and that was always gonna be a resume-enhancement point."Rush noted that Trump's rise results from the "force of his personality," but he warned conservatives about the billionaire."It's Trump that's out there talking about how he likes Pelosi and Reid, he could do deals with them if he had to," Rush said.Trump has openly bragged that his close relationships with House Minority Leader Nancy Pelosi and Sens. Harry Reid and Chuck Schumer, and said they will enable him to do "deals" with Democrats.Trump has been a longtime donor to Democratic candidates and committees, and backed Jimmy Carter, Walter Mondale, Hillary Clinton, and other leading Democrats.Limbaugh has not formally endorsed any candidate, but has made it clear that conservatives have only one choice in the GOP primary. Last month, Limbaugh told his radio audience, "If conservatism is your bag, if conservatism is the dominating factor in how you vote, there is no other choice for you in this campaign than Ted Cruz."Limbaugh gave his powerful imprimatur to Cruz by adding, "this [Cruz] is the closest in our lifetimes we have ever been to Ronald Reagan."