Two new polls of Hispanic voters underscore Donald Trump's steep challenge in carrying must-win Florida — and point to an ominous trend facing Republicans hoping to win America's biggest battleground state in the future.The Republican-leaning business group Associated Industries Florida polled 600 Hispanic voters in Florida Oct. 1-3 and found Hillary Clinton crushing Trump 54 percent to 30 percent. Compare that to four years ago, when Mitt Romney lost Florida after winning just 39 percent of the Hispanic vote in Florida.What's more, a separate poll of the fastest-growing segment of Florida's Hispanic electorate — Puerto Ricans — found three-quarters of the state's Puerto Rican voters plan to vote for Clinton and just 17 percent for Trump. The Republican nominee is virtually toxic among Puerto Ricans with 78 percent having an unfavorable view of Trump and 15 percent favorable, according to the poll of 504 Puerto Rican voters by the Democratic-leaning Center for American Progress Action Fund and Latino Decisions. Clinton was viewed favorably by nearly 7 in 10."When Donald Trump says Mexicans are rapists, Puerto Ricans understand he is talking about them, too. He is talking about us," Puerto Rican U.S. Rep. Luis Gutierrez, D-Ill., said in a conference call about the poll.About a million Puerto Ricans now live in Florida, roughly double the number that did in 2000. In the Orlando area, the population is exploding because of economic troubles on the island.Overall, Hispanic voters are likely to make up about 15 percent of the electorate, with nearly 30 percent of those voters Puerto Rican and slightly more than 30 percent Cuban-Americans, who are increasingly shifting away from the GOP.The sliver of good news for Trump is the AIF poll of all Hispanics found nearly 1 in 10 unsure about whom to support."If they come home to him, it's possible that Trump will perform closer to Romney's number with Florida Hispanics in 2012," Ryan Tyson, AIF's vice president of political operations, wrote in a memo. "However, the positive outlook ends for him there as Trump is down 44 (points) with non-Cuban Hispanics who will make up half of the likely Hispanic electorate. Trump will not win Hispanics here in Florida. However, if he can drive closer to 40 percent, then it's possible other factors could come into play that could keep this state competitive for him (i.e. Democrats experience a dip in minority voter turnout and/or continue to struggle with millennials)."The polls offer far better news for Sen. Marco Rubio, the Cuban-American Republican facing Democratic U.S. Rep. Patrick Murphy, who appears little known to most Hispanic voters. The AIF poll found Rubio with 48 percent support, Murphy with 39 percent, and 13 percent unsure.The Puerto Rican poll found 42 percent supporting Rubio and 44 percent backing Murphy, even though 47 percent said they did not know enough about Murphy. Rubio was viewed favorably by 41 percent and unfavorably by 43 percent.