It’s a commonplace bordering on cliché to lament that Truth is “the first casualty of War.” Yet in the battle of words between Presidents Trump and Zelensky the press has been quick to accuse America’s commander in chief of peddling lies. These columns don’t intend to go into the fact-checking business, which is too often warped by partisan bias. At the same time, one can acknowledge some of Mr. Trump’s concerns without losing sight of the war’s moral stakes.

The feud erupted between the two presidents Tuesday with Mr. Trump scolding Ukraine’s leaders for their apparent bungling in the leadup to the Russian invasion. “You should have never started it,” Mr. Trump declared. “You could have made a deal.” The invasion by Russia in February 2022 is not in dispute. Yet Mr. Trump’s remarks are of a piece with his assessment of what he called at that time a “very sad thing for the world and the country.” 

At that point, Mr. Trump, then a private citizen, reckoned that his successor in the White House, President Biden, “hadn’t done enough to dissuade Mr. Putin from invading,” as the Wall Street Journal put it. President Putin “was going to be satisfied with a piece and now he sees the weakness and the incompetence and the stupidity of this administration,” Mr. Trump told Fox News shortly after the Russian troops crossed over into Ukraine.

Could Mr. Zelensky have averted war by, say, forgoing membership for Ukraine in the North Atlantic Treaty? Would any concessions by Ukraine, short of a kind of neo-vassalage, have forestalled Mr. Putin’s designs on the former Soviet — and Russian — province? Could savvier, and bolder, foreign policy by the Biden administration have stopped what has become a quagmire at an enormous loss of blood and treasure? 

These are all questions that are no easier to answer today than they were in the weeks before Mr. Putin’s invasion. So-called foreign policy realists, like John Mearsheimer, have stressed Russian fears over letting Ukraine into the North Atlantic Treaty. Russians fretted that “the American-led policy of making Ukraine a Western bulwark on Russia’s border and eventually bringing it into NATO would directly threaten its security,” as Mr. Mearsheimer writes.

Those Russian fears go back as far as 2008, when the American envoy to Moscow at the time, William Burns, called Ukraine joining NATO “the brightest of all red lines for the Russian elite,” seen as “a direct challenge to Russian interests.” Skeptics have wondered whether America’s post-Cold War expansion of NATO to include Eastern European countries that were once part of Russia’s sphere of influence was a provocation.

Yet even if Mr. Trump is correct that the war “never would have started” had he remained in the White House, the fact remains that Mr. Putin did, in the event, launch a war against the Ukrainians, who show no sign of wanting to fall again under the Kremlin’s suzerainty. The question at hand is how, or if, the war can be brought to an end while preserving Ukraine’s independence, which Secretary Rubio and Vice President Vance tout as an imperative.

To that end, mocking Mr. Zelensky, however frustrating he may be, strikes an off-putting note. It strikes us as an unwise bet to appease Russia under the presumption that, as Mr. Trump puts it, “this War is far more important to Europe than it is to us.” It’s not silly for Mr. Trump to mark that “We have a big, beautiful Ocean as separation.” George Washington himself spoke of America’s “detached and distant situation” in his farewell address.

That ocean, though, has been sailed by various factions. In the years before World War II, it was kvelled over by the isolationists who sought to keep America out of the brewing conflict — until the Japanese sprang upon Pearl Harbor. It was Senator Vandenberg who marked early in the Cold War that it was wise to defend our allies overseas because “we are the final target, though other independent peoples are in nearer jeopardy.”