“The American people should not wonder where their military leaders draw the line between military advice and political preference,” Dempsey wrote in a letter to the Washington Post. “And our nation’s soldiers, sailors, airmen and Marines should not wonder about the political leanings and motivations of their leaders.”

The role of the military is set out in the Constitution and is based on trust, Dempsey told NPR’s Renee Montagne. Delving into politics undermines that trust, he said.

“I was upset,” he said, about generals at the conventions, “not at the two individuals, necessarily, but that somehow, the message that we have been sending about the proper role of senior leaders, both on active duty and beyond, had not made it every place it needed to make it.”