European leaders are putting Ukraine in an untenable position.

The political formula was imposed by Russia as part of what is known as the “Minsk 2” agreement in February. Germany, France and Ukraine agreed to the deal in a desperate effort to stop an escalating military conflict. The shooting diminished, but never stopped; Russia and its proxies have never respected the cease-fire. Yet now the German and French governments have enlisted the help of the Obama administration in seeking unilateral Ukrainian compliance with Minsk 2’s onerous political terms, which if fully implemented would implant a Russian-controlled entity inside Ukraine’s political system.

U.S. officials say Ukrainian steps toward compliance put pressure on Russia and deprive it of a pretext for launching another full-scale military offensive. But Moscow’s aggressive propaganda apparatus relentlessly portrays Ukraine as violating the deal; and Mr. Putin hasn’t needed a legitimate pretext for his previous aggressions. Even if Russia respected the cease-fire, the terms it seeks for reincorporating the areas it holds into Ukraine would cripple the country’s democracy and independence — which is Mr. Putin’s goal.

Rather than legitimize Russia’s puppet entity, Ukraine would be better off leaving it isolated and forcing Moscow to sustain it, as it does similar enclaves in Georgia and Moldova.