WASHINGTON — When Adm. Harry B. Harris Jr., the military’s top commander in the Pacific, ordered the aircraft carrier Carl Vinson “to sail north” from Singapore this month, he was oblivious to the larger — and incorrect — impression that he was rushing a naval strike force to confront an increasingly belligerent North Korea.

Four days later, when Gen. John W. Nicholson Jr. dropped the most powerful conventional weapon in the American arsenal on Islamic State fighters in a tunnel complex in eastern Afghanistan, he not only seized headlines around the world but also unintentionally signaled to dictators in Syria and North Korea that they might be the next target of what the Pentagon called the “mother of all bombs.”

Instead of simply achieving tactical objectives, the timing of their actions surprised their bosses at the Pentagon, upset edgy allies and caught the White House flat-footed. Taken together, the episodes illustrate how even the military’s most seasoned four-star field commanders can fail to consider the broader political or strategic ramifications of their operational decisions, and some current and former senior officials suggested that President Trump’s decision to unshackle the military from Obama-era constraints to intensify the fight against terrorists risked even more miscues.

“There are lots of decisions that military commanders make every day on their own without asking, ‘Mother, may I?’” said Robert M. Scher, a former senior Pentagon official. “But they have to realize and take into account that their actions can have strategic impact outside of their areas of responsibility.”