DORAL, Fla. — Jorge Ramos, the Univision and Fusion television anchor who is often called the Walter Cronkite of Latino America, was in his suburban Miami broadcast studio when he all but pounced on the chairman of the Republican Party, Reince Priebus, who was appearing from Washington. The Republicans’ immigration policy is “deportations, deportations, deportations,” Mr. Ramos said. “Why?”

Mr. Priebus, who stared out from multiple screens in a control room here looking as if he would rather have been doing anything but talking to Mr. Ramos, insisted it was not so. But Mr. Ramos would not have it.

“The message,” he retorted, “is anti-immigrant.”

For years, Mr. Ramos largely aimed his ire at President Obama for breaking his 2008 campaign promise — made directly to Mr. Ramos — that he would propose an overhaul of the nation’s immigration system in his first year in office, and for deporting two million people since. Even after Mr. Obama announced late last year that nearly half of the estimated 11 million undocumented immigrants could apply to work without fear of deportation, Mr. Ramos confronted him during a Nashville forum for having “destroyed many families” by not acting sooner.

But Mr. Ramos’s focus has changed, he said in an interview here: “Now is the turn of Republicans.”

This weekend, the Spanish-language Univision, and Fusion, its English-language venture with ABC News, will cover the first gathering of 2016 Republican presidential aspirants, at a conservative forum in Des Moines on Saturday organized by Representative Steve King of Iowa. Mr. King, an immigration hard-liner, is well known to Latinos for remarks like one claiming that most young border-crossers have “calves the size of cantaloupes because they’re hauling 75 pounds of marijuana.”