The presidency has changed Barack Obama. His hair has gone gray, which is to be expected, and he looks older, which is also to be expected, but his eloquence has been replaced by petulance and he has lost the power to persuade, which is something of a surprise. You can speculate that if the Barack Obama of today and not Winston Churchill had led Britain in World War II, the Old Vic Theatre Company would now be doing “Hamlet” in German.

The president has lost his voice, that is certain. The numbers say so. Obama has the approval of only 44 percent of the American people. During his time in office, Congress and much of the nation has gone Republican — statehouse after statehouse, governor after governor (soon to be 32) — an astounding feat when you consider that the GOP has become the Know-Nothing Party in all its meanings.

It’s not that Obama has lost his gift of eloquence. His problem is that he often has nothing to say. When he does, as after the mass murder in June at a Charleston church, he can be moving and eloquent. It is on foreign policy particularly where he goes empty and cold. His policy, after all, is to avoid yet another Middle East quagmire. It entails the ringing call to do as little as possible.

Obama’s self-inflicted predicament was apparent in the statement he issued following the Paris terrorist attacks. Unlike many other mass killings, this one was broadcast in real time — unfolding on TV as it happened. It left America both shaken and horrified. Yet Obama spoke coldly, by rote — saying all the right things in the manner of a minister presiding at the funeral of a perfect stranger.

The president is capable of better, and indeed, after some criticism, he eventually did better. But he is a cautious man who fears his rhetoric running away from him. This happened once before, when he issued his “red line” warning to Syria — and then, upon consideration, said never mind. The result has been a foreign policy debacle where the measure of him was taken. He’s been bullied off the playground.

Obama’s dilemma is not just that he cannot find the words to articulate his policy. He cannot even stick to it. His initial reluctance to act in Libya faded when Moammar Gaddafi threatened to massacre his opposition and the French took the lead. His determination to stay out of Iraq collided with the threatened genocide of the Yazidis. Iraq fell apart, the Islamic State seemed to come out of nowhere. Americans were beheaded. Women were enslaved. No boots on the ground became some boots on the ground — and then some more and then some of them helped the Kurds and mixed it up with the Islamic State. Reality rebuts the policy and it unravels by degree.

George W. Bush’s Iraq War was a lesson to us all. But from the start of the Syrian crisis, no one sane was proposing doing it all over again. Instead, the proposal was to intervene early and attempt to avoid the bloodbath and humanitarian calamity that have resulted. The idea was to do more than simply tell Bashar al-Assad to return to his ophthalmology practice in London and for the U.S. and its allies to actually take some action — like grounding his helicopters. And when it came to the Islamic State, the proposal was to do more than make some initially inadequate bombing runs, but actually put spotters on the ground and train anti-Assad fighters who had a stake in the fighting. As it was, America managed to assemble an army of about half a dozen.

Obama is confined by the prospect of another Iraq. He defends his policy of minimalism with an off-putting petulance: “If folks want to pop off and have opinions … .” He talked of seeing at Walter Reed Hospital “a 25-year-old kid who’s paralyzed or has lost some limbs … and so I can’t afford to play some of the political games that others may.” Yes, some of the Republican presidential candidates are playing games, but Obama’s critics in think tanks and elsewhere are deadly serious. Besides, life presents mean choices. Limbs were lost in Paris, too.

To a large degree, Obama became president on the strength of his eloquence. To a large degree, that is what has deserted him. He is out of words because he is out of ideas. Consequently, he ought to listen to others. They’re not the ones who are popping off. He is.

Richard Cohen is a columnist for The Washington Post. His email address is: cohenr@washpost.com.