Each May 9, the country celebrates its victory over the Nazis in World War II—and this year it may reportedly declare war against a country that the Kremlin absurdly claims is run by neo-Nazis: Ukraine.

When President Vladimir Putin announced the invasion of Ukraine on February 24, he did not declare war. Instead, he called it a “special military operation.”

Of course, that didn’t mean Putin wasn’t launching a war—he plainly was. But he didn’t call it a war, and that was far from unusual.

Indeed, since World War II, it has been exceedingly rare for countries to formally declare war on other countries.

The aftermath of that great conflict saw the creation of the United Nations and its Security Council, largely with the goal of preventing new wars. These structures provide an international legal framework for waging war, which can only legitimately occur either in self-defense or through collective action by the Security Council.

That makes standalone war declarations legally risky, which can trigger difficulty in building coalitions down the line, and in managing relations with neutral countries.

Nonetheless, CNN reported Tuesday that Putin may declare war on Ukraine next week, more than two months after the war actually began.

The report cited U.S. State Department officials, plus British Defense Secretary Ben Wallace, who last week theorized that Putin would make the move “to mass mobilize the Russian people.”

This would partly be a matter of using the declaration to convince the Russian people that the conflict is serious and their government is doing the right thing. Politically, it would make it even harder for Putin to back down without losing face.

But in practical terms, a declaration of war would also allow the Kremlin to boost its manpower on the ground in Ukraine.

Russia routinely conscripts young men, usually for a term of one year, then adds them to a reserve pool that numbers over two million. They are not supposed to be sent to fight outside Russia—when the government said six weeks ago that some conscripts had been captured in Ukraine, it was an embarrassing admission.

A general mobilization, and the introduction of martial law in Russia, would make it much easier to tap into this resource.

Green conscripts and out-of-shape reservists do not generally make for elite fighters, but Putin may have little choice as Russia’s experienced soldiers are getting slaughtered.

It is notoriously difficult to establish accurate death tolls while wars are ongoing, but Ukraine claims nearly 25,000 Russian troops have been killed since hostilities began.

Whatever the true toll, the British defense ministry said Tuesday that Russia’s military was “now significantly weaker, both materially and conceptually, as a result of its invasion of Ukraine.”

As U.S. State Department spokesman Ned Price put it in the CNN article, a Russian declaration of war aimed at “surging conscripts” would ironically “be tantamount to revealing to the world that their war effort is failing, that they are floundering in their military campaign and military objectives.”