As Ukraine war drags on, NATO steps up war readiness

When two Russian fighter jets forced down an American surveillance drone above international waters a week ago, U.S. officials warned that the “reckless” move ratcheted up the risk of “miscalculations” and “misunderstandings” between the two nuclear powers. 

Back at NATO’s strategic headquarters in a small village an hour southwest of Brussels, it was yet another incident driving home the urgency of the question keeping its planners busy around the clock: How, precisely, will NATO respond if Russia, either accidentally or intentionally, attacks a member the alliance has pledged to defend?

“Now this is...