I just finished reading James McPherson's Battle Cry of Freedom. In his extensive discussion of the lead up to the War, he talks of the pre-Civil War court as being one largely dominated by Southerners and conservatives. In cases such as Dread Scott (1857), they upheld the institution of slavery.
How quickly did the make-up of the Court change with the election of Lincoln and the Republicans? And how much, if any, resistance did the Court pose for Republicans and their political and war aims?
Chief Justice Roger Taney, who was a native Marylander, was strongly opposed to Lincoln's suspension of the writ of habeas corpus in his home state. He vowed to rule against such practices if they came across his desk.
So Lincoln appointed a 10th justice, Salmon P. Chase, to the Court, effectively ensuring a tied ruling on partisan issues. The Constitution did not set the number of justices firmly at 9 and Lincoln took advantage of that fact. Not to mention that Chase was a political rival and giving him a lifetime appointment elsewhere was good for Lincoln, too. The Judiciary Act of 1869 set the number firmly at 9.
FDR tried to overturn the Judiciary Act and pull the same kind of trick when the Court started to push back on New Deal programs but he was unsuccessful.