Blockading is an act of war, and against a state that has not even participated the commonly accepted "cause" for blockading this shows Lincoln to be the agressor. Do you know if he did the same to North Carolina?
I've actually been wondering myself how to go about examining Lincoln's beliefs and positions - not just for what he did but for the true underlying beliefs.
The problem is that the many contradicted himself so thoroughly very little tangable substance may be asserted with certitude. The most I believe that can be said for even his supposed greatest issue, slavery, is that Lincoln had a very general passive moral opposition to the institution. At times he spoke and wrote positions far more solid and direct than this, but elsewhere he contradicted them completely. The sole major issue I can find that he consistently stuck with the same position on throughout his entire career was protectionism.
The only rational explanation for it all is that trying to find certitude in Lincoln's beliefs is a futile exercise. It is futile because everything he did beyond the vaguest passive underlying levels was politicized to the extreme. It all points to an ultra-modernist figure weilding power in the fashion one would expect to find in a situation unrestrained by matters of certitude, truth, constancy, and acceptance of a tangable reality.
Lincoln ordered Virginia and North Carolina included in the blockade on the same day, April 27, 1861. North Carolina didn't convene a secession convention until May 20th. Federal warships had been seizing Southern merchant ships since May 1st, and naval vessels had cannonaded Virginia militia batteries on May 9th and May 18th. The latter attack was at Sewell's Point (now part of Norfolk Naval Base, opposite Fort Monroe), and is considered by some contemporary historians to be the opening of Lincoln's military campaign against Virginia.
On the same day North Carolina seated its convention, May 20th, United States marshals, acting under Lincoln's orders, seized all the telegraph correspondence in the U.S., in order to examine it for "evidence" of pro-secessionist views.
As of April 27th, the day Lincoln ordered North Carolina blockaded, to answer your question, the Tarheels hadn't done squat and were still United States citizens and members of the Union.
The Confederate congress had passed a bill, and Jefferson Davis had signed it on May 6th, stating that a state of war now existed between the Confederacy and the United States, but until May 20th, North Carolina was still in the Union. Virginia was arguably out as of April 17th, when the secession convention voted Virginia out, but the ratifying plebiscite wasn't held until May 23rd. The actual dates when North Carolina and Virginia officially joined the Confederacy and became de jure belligerents would need further research, but the state of belligerency was arguably initiated by Lincoln's blockade, which was and is an act of war, not a police action, on April 27, 1861.
Lincoln's blockade of Virginia and North Carolina was a violation of Article I, Section 9, of the Constitution, which says in relevant part:
"No Preference shall be given by any Regulation of Commerce or Revenue to the Ports of one State over those of another: nor shall Vessels bound to, or from, one State, be obliged to enter, clear, or pay Duties in another."
Lincoln's blockade clearly violated that clause of the Constitution.