Days after Lithuania said its intelligence services had caught Russia preparing sabotage against the infrastructure that ties the Baltics to Europe, Foreign Minister Kestutis Budrys drew a public line. If those plans are carried out, he said, Vilnius will not treat the results as accidents. “If there is damage, or if there are casualties, it will be treated as an act of aggression, with all the due consequences,” Mr. Budrys said in an interview with The Washington Times at the foreign ministry. That means, he added, “not only the country’s self-defense but the collective defense of the alliance.” The warning,...