IN a recent speech in London, Gen. Stanley A. McChrystal, the top United States commander in Afghanistan, was blunt. Calling the military situation there “deteriorating,” he warned that the United States was going to have to “do things dramatically and even uncomfortably differently.” General McChrystal had already submitted a report, somehow leaked, requesting an additional 40,000 American troops. He acknowledged in his speech that in so speaking out while the issue was still under debate in the White House, he might have difficulties with his superiors.

Comparisons have been made between this situation and the unfortunate instance in 2003 when the Army chief of staff, Gen. Eric K. Shinseki, was punished for advising Congress of the enormous effort it would take to defeat and pacify Iraq in any meaningful way. General Shinseki was not removed outright, but he was treated shabbily by the Bush administration in more subtle ways until his retirement later that year. But the two cases were different. General Shinseki was testifying under oath before Congress; General McChrystal was speaking voluntarily, on his own.

As a former Army officer, I tend to be sympathetic to the generals who are placed in impossible situations, created partly by the framers of the Constitution in 1787. They designated the president as the commander in chief, but at the same time they gave Congress the power to raise and support armies and navies.

This division of authority between two branches of government puts the head of a military service in an untenable position. Officers owe their loyalty to the president and have an obligation to resign if they are unable to carry out the commander in chief’s policies. At the same time, they must sometimes testify under oath to the Congress. Trapped in this way, most officers elect wisely to keep their public opinions vague.