What was once furious Republican opposition to Donald Trump's proposal to temporarily ban foreign Muslims from entering the U.S. has turned to virtual silence in the face of widespread GOP voter approval.

Exit polls from the nation's biggest Republican primaries show impressive majority support for Trump's proposal. In the latest example, in Pennsylvania Tuesday, 69 percent of GOP voters said they support "temporarily banning Muslims who are not U.S. citizens from entering the U.S." In New York last week, the number was 68 percent.

In Wisconsin, 69 percent supported Trump's idea. In Florida, 64 percent. Georgia, 68 percent. Ohio, 65 percent. Michigan, 63 percent. New Hampshire, 65 percent. Texas, 67 percent.

Huge majorities across the country in states won by Trump and states won by Ted Cruz — and even the one state won by John Kasich. If those exit polls, measuring the opinions of tens of thousands of people, are correct, the temporary foreign Muslim ban has become a Republican staple.

Indeed, approval is so extensive that Trump's proposal is rarely the subject of extended discussion today. But it set the race on fire when Trump introduced it last December. And some of its most vocal opponents were leading figures in the Republican Party and the conservative world.

All of Trump's rivals in the 2016 race said they disagreed with the proposal. Some used stronger terms than others: Jeb Bush called it "unhinged," while others called it "idiotic," "fascist," "racist," and "dangerous." House Speaker Paul Ryan called the plan unconstitutional and "not what this party stands for and, more importantly ... not what this country stands for." 2012 presidential nominee Mitt Romney accused Trump of "scapegoating" Muslims. Karl Rove called it "stupid." Former Vice President Dick Cheney said Trump's proposal "goes against everything we believe in."

Influential Southern Baptist Convention official Russell Moore called it "reckless, demagogic rhetoric" that "would make Jefferson spin in his grave." Various writers at National Review and the Weekly Standard condemned it. Charles Krauthammer called it "absurd."

That was then. No doubt those critics still believe what they believe, but two-thirds support among Republican voters has changed the playing field. The white-hot controversy of December is no longer even warm.

Trump has moved the Republican debate on all sorts of subjects — trade, immigration, entitlements and more. In the case of temporarily banning foreign Muslims, Trump created an issue out of whole cloth, stuck to it through an enormous controversy, and, with voter approval, appears to have come out ahead in the Republican race.