Opinion | Everyone Wants to Seize Russia’s Money. It’s a Terrible Idea.

The Republican House speaker, Mike Johnson, has brought a glimmer of hope to supporters of the Ukrainian war effort. He suggested to Fox News on March 31 that he would try to rally his divided party behind the so-called REPO Act. That piece of legislation would allow President Biden, working with European allies, to seize Russian currency reserves frozen in the West and use them to aid Ukraine.

Grabbing these reserves would be politically convenient. Since Russia’s invasion of Ukraine in February 2022, the United States and its allies have thrown more than a quarter-trillion dollars into the war, to little ultimate effect. Ukraine has lately suffered a string of battlefield defeats. Prolonging the war is a project that Americans of all political leanings have been steadily less willing to fund through taxes.

Mr. Johnson backs Ukraine’s war effort, and sees supporting it as a responsibility of American leadership. But his caucus — more in tune with the Republican voter base — has stymied him. The REPO Act might offer both Mr. Johnson and Mr. Biden a way to duck controversy.

Thus far, the idea of supplying Ukraine through a spending bill has brought scorn from congressional Republicans who wonder whether Americans’ taxes wouldn’t be better spent on defending the U.S.-Mexico border. The REPO Act, by contrast, could make “Russia foot the bill for its own aggression,” as a group of Brookings Institution scholars puts it. Mr. Johnson himself calls it “pure poetry.” It is a tempting idea.

But it is a bad one. In any free country there is a constitutional wariness of allowing the government to do anything without levying taxes, for good reason. Taxes and accountability go together. Generally, if citizens aren’t paying for a government program through taxes, they are paying for it in some less straightforward way — by taking on debt, for instance, or permitting an outsize governmental role for some corporation or other private interest.

The REPO Act carries additional risks. The very act of seizing Russian assets would pose dangers to the U.S. economy, because other countries, not just Russia, would view it as an act of brigandage. This could weaken the dollar’s status as the main global reserve currency.