It’s is hard to say at this juncture whether President Biden’s imprecation Saturday about President Putin — “For God’s sake,” Mr. Biden exclaimed, “this man cannot remain in power” —  is a cri de coeur, a gaffe, or a turning point in American foreign policy. As the president spoke in front of the palace at Warsaw, one could almost hear the gasp of the pundits.

Yet no sooner had the president spoken than his staff tried to stuff the genie back into the blasted lamp. “The President’s point,” the White House waffled, “was that Putin cannot be allowed to exercise power over his neighbors or the region. He was not discussing Putin’s power in Russia, or regime change.” Our own view is that the president would do better to get himself a new amanuensis.

Mr. Biden’s Warsaw declaration could yet be the finest moment of his meager presidency. Certainly the cadences that he used contrasted favorably with the instinct for appeasement that has marked his administration so far. Would that Mr. Biden had made such remarks in respect of the Iranian ayatollahs, say, or of the Taliban in Afghanistan, or before the savaging of Ukraine — or now, in respect of Taiwan.

Not that any of this would be easy. Were Mr. Biden intent on ridding the Kremlin of President Putin, it would take a lot more than mere words. Sanctions would have to be not only maintained but sharpened, even if it hurts the West. More and better weapons would have to be sent to Ukraine, and a way found to encourage dissidents within Russia. Mr. Putin’s brazenness demands a strategy, a la Reagan.

A new assessment of the war in Ukraine is emerging, though, one that allows for the possibility of neither the triumph of a Russian blitz nor the inevitability of a grinding occupation but rather for something like an outright Ukrainian victory. We don’t want to get ahead of our skis here, or, as we put it the other day, “we don’t want to declare victory prematurely,” even if “the idea of independent Ukraine looks alive.”  

So let’s not forget that Russia has a diverse quiver of nuclear weapons. Even if Ukraine succeeds in foiling Mr. Putin’s westward advance, there would still be the battle to unclaw his grip on power at home. This is where Mr. Biden needs to be clear and stand by his words, rather than send out a spokesperson to walk them back. That kind of waffling no doubt helped embolden Mr. Putin in the first place.