As president, Thomas Jefferson campaigned against the U.S. Supreme Court in the pivotal 1800 election after the court let the Alien and Sedition Acts stand. The law criminalized criticizing government officials of the U.S. Government. Lincoln announced during his 1860 campaign that he would not enforce the court’s Dred Scott decision upholding slavery in U.S. territories. In saying that invalidating the Affordable Healthcare Act would represent an unprecedented act of judicial activism, Obama was not going nearly that far. In other words, he was not saying he would ignore the decision. Nor did Obama announce anything like Roosevelt’s unsuccessful court-packing scheme.
The full essay is at "Obama on the U.S. Supreme Court."