... In 2022, after eight years of intermittent fighting in Ukraine’s east, Russia initiated a full-scale invasion, with the aim of reducing a rump Ukraine to a satrapy. Putin has given no indication of renouncing that ambition or of abandoning his broader goal of restoring Moscow’s sway over much of the former Soviet or tsarist empires, including the Baltic states and other nations to Russia’s west. Any “deal” between Trump and Putin (and the U.S. president, who has more recently referred to a “feel-out” meeting, is clearly downgrading expectations) will, given the Kremlin’s longer-term objectives, never be enough. The best...