WASHINGTON – With no Republican in the presidency, the voice of the Grand Old Party is clearly up for grabs these days, and Donald Trump, the loudest mouth on the scene, is doing an effective job of claiming the distinction, though he has never held a political or public office of any kind.

No figure who ordinarily might be recognized as the GOP spokesman – a former Republican president, former presidential nominee, former secretary of state or big-state governor – has stepped up to speak for the party of icons Teddy Roosevelt, Dwight Eisenhower and Ronald Reagan, leaving the field for Trump to dominate with his bombast and bigotry.

But his latest outrage of calling for all Muslims to be barred in response to the global terrorist threat from the radical Islamic peril has finally stirred one forthright party leader. Paul Ryan, the new Speaker of the House, has given meaning to his just-acquired job title by saying of Trump’s demand: “This is not conservatism.” It is “not what this party stands for and, more importantly, it’s not what this country stands for.”

Ryan had vowed not to comment on the candidates seeking the next Republican nomination but now said he was making an exception. “Some of our best and biggest allies in the struggle and fight against radical Islamic terror are Muslims,” he said, “the vast, vast, vast majority of whom are people who believe in pluralism, freedom, democracy, individual rights.”

The 2012 Republican vice-presidential nominee, who has disavowed interest in seeking the 2016 presidential nomination, has thus rushed in where the declared GOP White House aspirants only belatedly have dared to tread.

They obviously fear alienating the broad electorate in the party that has fallen in a remarkable way for the billionaire front-runner.

They may hope, like Sen. Ted Cruz of Texas, to inherit the Trump support if he somehow falters, and meanwhile they limit their opposition to mild rebuffs, such as Jeb Bush’s comment that Trump has become “unhinged.”

But Ryan has served up a strong hint that he intends to be the speaker not only of the House but also a prime defender of the party itself as it faces an uncommon identity crisis. Having Trump as its presidential nominee not only would risk major defeat in 2016; it would put in jeopardy its reputation as a serious political institution.

Ryan’s declaration has finally stirred a few timid souls in the party leadership like Senate Majority Leader Mitch McConnell and Republican National Committee Chairman Reince Priebus to disagree with Trump.

McConnell told CNN he found Trump’s would-be excommunication of Muslims “completely inconsistent with American values.” Presidential candidate Sen. Marco Rubio tut-tutted that Trump’s “habit of making offensive and outlandish statements will not bring Americans together.”

At the same time, however, Ryan when asked whether he would support Trump if nominated by their party, said rather incongruously: “I’m going to support whoever the Republican nominee is, and I’m going to stand up for what I believe in as I do that.” That sounded more like a prayer that it won’t be Donald Trump, and all the other candidates are saying it to themselves, after vowing in the first debate among them to support the eventual nominee.

Cruz meanwhile seems to want it both ways. “I disagree with that proposal,” he said on Capitol Hill, then adding: “I like Donald Trump.” He said he was “not interested in” attacking the current favorite for the nomination.

At next Tuesday’s Republican presidential debate in Las Vegas, the other Oval Office hopefuls on the stage no doubt will face questions on where they stand on Trump’s radical no-Muslims-allowed proposal. Their responses may say as much or more about their own chances to remain viable in the crowded field than about Trump’s hold on his commanding lead in the polls up to now.

The front-runner’s latest excesses have provided the party establishment its best grounds to date to rally the old faithful to save its good name, if only they can agree on a unity candidate.

Jeb Bush thought he would be it, but with his stock falling and the GOP establishment itself in such bad odor within the party, there seems no moderate savior in sight.

Editor’s note: Jules Witcover’s latest book is “The American Vice Presidency: From Irrelevance to Power,” published by Smithsonian Books. You can respond to this column at juleswitcover@comcast.net.