During the ceremony, Putin said the four provinces — Luhansk, Donetsk, Kherson and Zaporizhzhia — will be folded into Russia and will be protected by “all available means.” They will join the Crimean peninsula, which Russia annexed after its more limited initial invasion of Ukraine in 2014. The annexations represent a violation of international law and the vast majority of nations won’t recognize the territory as Russian. The expected pronouncement had been met with fresh warnings this week that Russia will be even more isolated internationally, amid fears that Putin will use the declaration as a pretext to escalate the...