Non-public conduct of national security policy does not in itself pervert the Constitution.
No, certainly the government needs to keep secrets.
But the --Congress-- had passed legislation that the executive branch was bound to obey -- the Congress makes law, not the executive branch. But the Reagan administration -- none of this is at all controversial or new-- conducted affairs in secret, went outside the letter and spirit of the Constitution and secretly funded an army with proceeds from the sales of U.S. government property.
Secretary of State George Schultz is well on the record as having opposed these activities. He was overruled.
None of this is at issue, but I do welcome your comments, because it certainly puts your condemnation of President Lincoln in a different light.
Walt
Congress can and does legislate policy and induce that policy to be executed by the president, but Congress has not constitutional right to dictate the policy of the president for him or deny him his own right to formulate non-legislative policy. Denying the president this right is a form of legislative veto, which the supreme court has ruled unconstitutional.