What was President Abraham Lincoln's first response to the situation at Fort Sumter?

Lincoln said he would send food but no arms to the fort.

He could not actually declare war, because that would have meant recognising the Confederacy as a sovereign nation.

But he did the next best thing - appealed for volunteer troops. He called for 75,000 volunteers to fight the insurrection. Four states of the Upper South joined the Confederacy. The two sides were lined-up. The war was on.