Until his ignominious fall last week, British Prime Minister Boris Johnson could count on unstinting support from at least one quarter: Ukraine. President Volodymyr Zelenskyy claimed to be “very happy” last month when a flailing Johnson won, narrowly, a vote of no-confidence in his leadership of the Tory party.

Only last week Johnson was dialing the Ukrainian leader’s phone number after being caught lying about his promotion of a serial groper — the scandal that finally brought him down. Indeed, strategically timed conversations with Zelenskyy had become Johnson’s preferred distraction from his scandal-battered government in recent weeks.

It is not clear what was discussed in these numerous conversations. As the columnist Simon Jenkins wrote, “All we know is that on almost every occasion, Johnson conjures from the air another tranche of British taxpayers’ money in aid for Ukraine.”

In Germany, Ukrainian Ambassador Andrij Melnyk has made much stronger interventions in local politics through his tweets and talk show appearances. Comparing German Chancellor Olaf Scholz to a “liverwurst,” he has tried to mock and berate Berlin into taking a more activist stance on Ukraine.

Taking sides in the domestic politics of its allies would seem an unwise strategy for Ukraine under any circumstances. It’s doubly so now, when taxpayers in Western Europe and the United States risk tiring of spending money to support a war where victory seems increasingly elusive.

The rapid Western political and media consensus on Ukraine, understandably, did not emerge from any extensive public debate or discussion. Rather, politicians and editorialists reveling in the newfound unity of the West counted upon popular feelings — spontaneous revulsion against Vladimir Putin’s unprovoked assault on a sovereign country and people, and reflexive admiration for the courage shown by Ukrainians against a brutal and unscrupulous enemy.

But feelings and sentiments change much faster than the policies they help create. Western interventions in Afghanistan and Iraq are recent examples: Initially popular, they eventually helped Donald Trump’s improbable rise to power as, in part, an anti-war candidate.

Such reversals occur because ordinary citizens don’t, and can’t, share the reasons why many politicians and journalists continue to strike combative postures long after they cease to be effective.

Politicians in democratic countries tend to find in war abroad a scope for bold maneuver and rhetoric unavailable to them at home: Late last month U.S. President Joe Biden briefly stood tall at the head of a seemingly rejuvenated NATO in Madrid before returning to his hopeless battles for gun control and abortion rights in Washington, D.C. Journalists and commentators in affluent societies — from Ernest Hemingway to Bernard Henri-Levy — have long been prone to seek moral seriousness (and self-promotion) in other people’s wars.

People who don’t belong to any political or media establishment lack such professional and ideological motivation. They are also more exposed to economic adversity and disposed to change their minds about forever-seeming wars.

As it happens, ordinary citizens were never adequately informed about the steep economic and military risks of a prolonged war against a nuclear and commodity superpower.

Western strategists and commentators highlighted Russia’s military failures and economic frailty in the early stages of its assault on Ukraine. But they barely considered how, unlike the despots of North Korea and Iran targeted by Western sanctions, Putin was willing and able to unleash a global energy-and-food crisis in retaliation.

Nor did they foresee that, as China and India eagerly buy discounted Russian oil, and non-Western countries refuse to sanction Russia, the Kremlin’s revenues would actually rise instead of falling.

The ruble is not exactly being reduced to “rubble,” as Biden promised. Rather, every day now brings fresh fears of impending disasters in even highly developed economies. Russia’s gas pipeline to Germany is due for routine servicing and closure this week. If, as seems likely, Putin doesn’t turn the tap back on fully, Europe’s strongest economy could plunge into a deep recession.

Amid mass unemployment, public sympathy in Germany for Melnyk, Ukraine’s sharp-tongued diplomat, will dwindle. Zelenskyy, too, is in danger of losing some of his enormous moral capital in the U.K. after his unstinting support for Johnson.

Certainly, public opinion in Europe is already shifting fast as record-high inflation fuels fears of a devastating economic crisis. According to an opinion poll conducted in 10 European countries by the European Council on Foreign Relations last month, those who want the war to end as soon as possible outnumber those who seek to punish Russia.

That majority in the West is very likely to grow; it could even become indifferent to the fate of Ukrainians as the economic outlook worsens. Abandoning Ukrainians to their ruthless persecutor would be as much a disgrace as abandoning Afghans to the Taliban was. Yet we must prepare ourselves for the grim possibility that another hasty and ill-conceived intervention backed by political and media elites will become a messy failure, hurting the very people it was supposed to help.

Bloomberg Opinion columnist Pankaj Mishra is author, most recently, of “Run and Hide.”