The publication of portions of the Pentagon Papers despite President Nixon’s threats of treason highlighted the fact that four presidents successively lied to the American People on build-up of U.S. involvement in Indochina (most notably, Vietnam) and the Nixon administration lied on the prospects for victory in the Vietnam War—a war that had not even been declared by Congress. Clearly, democratic accountable extends to foreign policy at least in broad outline, such as in whether or not to continue an active engagement militarily in another region of the world. Even in U.S. presidents being able to get away with effectively declaring war even as one of their roles is that of commander-in-chief—a huge conflict of interest!—democratic accountability by the popular sovereign, the People—is important, even vital should the legislative and judicial branches fail as checks in the separation-of-powers feature of the U.S. Constitution.
The full essay is at "Democratic Accountability on the Vietnam War."