In Beijing, the ripple effects of a move that may cost China dearly are now sinking in, say the officials and advisers. Some officials say they are fearful of the consequences of getting so close to Russia at the expense of other relationships—especially when Russian aggression against Ukraine is isolating Moscow in much of the world.

Already, many politicians from Washington to Brussels have grouped Beijing together with Moscow as a new “axis”—a term giving Western alliances more reason to disengage from China and form closer ties among themselves.

“Elevating the partnership with Russia on the eve of its invasion of Ukraine was a massive foreign-policy blunder by Xi,” said Jude Blanchette, a China specialist at the Center for Strategic and International Studies, a Washington think tank focused on international relations. “The cost is very real for China and is exposing the limits of Xi’s policy.”