f Donald Trump returns to the presidency and tries to halt or drastically reduce U.S. military, economic and humanitarian support to Ukraine — as he has indicated he would — Ukraine would not be the only country to suffer. Russia’s likely resulting gains in the conflict would further destabilize Europe and undermine U.S. credibility worldwide. Work must be done before the 2024 election to put Ukraine in the best possible position to endure whatever a newly elected Trump might do. The Biden White House is already warning Congress that if it doesn’t authorize more Ukraine aid soon, the spigot will...