"Doing so without the approval of Congress as Lincoln did was entirely against the US Constitution."
RDFX.
I am not sure that is entirely correct. The constitution requires him to protect the United States from all danger, both foriegn and domestic. In this case the danger was domestic and it was with in his perview to do what he did. I am not sure, but by the time the blockade went into effect he was operating under the war powers act that Congress activated. Kind of like what we have today with the present administration, all that he has done up to this time was granted him to do by Congress.
FC