Abraham Lincoln suspended certain constitutional liberties in order to make decisions. He had spent funds that Congress had not appropriated and blockaded Southern ports. Also, he banned “treasonable correspondence” from the United States mails. Lincoln had done this under his title of commander in chief.
Lincoln also had officially declared war on the South without a formal declaration. The formal declaration would mean he would go through Congress and he would have to wait for them to approve. However, he went ahead and declared war on the Confederates. This act by Lincoln ultimately caused many deaths in the Union and the Confederacy.