A sign it’s getting close to Election Day in Florida: Mitt Romney softens his immigration stance and his opponent’s new ads end with “ Soy Newt Gingrich y apruebo este mensaje.’’

Bienvenido a Miami.

With their gringo Spanish and Castro-crackdown plans, the two leading GOP candidates are flocking this week to this Latin American-influenced county where 72 percent of the roughly 368,000 registered Republicans are Hispanic. To date, about 54,000 Republicans have cast early and absentee ballots.

Romney heads to the Freedom Tower on Wednesday afternoon to talk Latin American policy. Gingrich will do the same Wednesday morning at Florida International University. Each is also dropping by the U.S. Hispanic Chamber of Commerce’s forum broadcast by Spanish-language powerhouse Univision. Rick Santorum and Ron Paul, who trail in the polls, are not making any scheduled appearances in Miami on Wednesday.

On Friday, Gingrich, Romney and Santorum are expected to appear before the Hispanic Leadership Network forum run by Sen. Marco Rubio and former Gov. Jeb Bush, a leader in Latino-Republican outreach. All three are scheduled to then meet with the mighty Latin Builders Association.

But they’ll all have some explaining to do after spending the past several months pandering to right wing voters in the early primary states, said Frank Sharry, who heads up America’s Voice, a liberal immigration reform group.

Now, the candidates must “square their right-wing rhetoric on things like English-only and immigration in a state that’s nearly a quarter Hispanic,’’ Sharry said.

The Republican candidates oppose the pro-immigrant DREAM Act, which many Hispanics support. Liberals are tarring them for being “anti-Hispanic’’ and a union group is bashing Romney with radio ads in Central Florida.

But Bush said it’s pure political posturing.

“Democrats have failed to deliver comprehensive reform,” Bush said in a written statement, noting that President Obama and a majority Democratic Congress didn’t pass the DREAM Act. “They have chosen to use these issues to drive a wedge.’’

The Service Employees International Union pounced on Romney’s debate comments on Monday when he said that people should leave the United States if they’re here illegally. He used the phrase “self deportation.”

“The self-deportation rhetoric,” SEIU’s secretary-treasurer, Eliseo Medina, said in a written statement, “shows a callous attitude towards the Hispanic community and a lack of understanding about what’s happening in the real world.”

The union is reinforcing that message in Tampa Bay and Orlando-area radio ads that are being financed by the pro-President Obama SuperPac, Priorities USA. The spots suggest Romney is “anti-Hispanic” — a faint echo of a Gingrich Spanish-language Miami radio ad that describe Romney’s positions as “anti-immigrant.”

But Romney on Monday explicitly softened his immigration stance at a debate. He said he didn’t want to physically deport those here illegally. And, for the first time in a debate, he endorsed a part of the DREAM Act that would give an immigrant a path to citizenship in return for military service.

“I would not sign the Dream Act as it currently exists,” Romney said. “But I would sign the Dream Act if it were focused on military service.”