We have divulging issues here. One is not providing full details on...x. The other is simply lying about...x. Both actually can be justified to the American people....under very specific conditions. Those conditions are usually only in a time of war, or when vital/important American assets, such as diplomats or military could be compromised if "the truth" of something specific to them is brought out
But those are very narrow arenas where lying to the American people is justified. Lying to cover one's ass of incompotence isn't one of them. Neither is lying to cover one's ass of irresponsibility.