The Obama administration has no contingency plan if the Supreme Court strikes down subsidies at the heart of ObamaCare, Secretary of Health and Human Services Sylvia Mathews Burwell said in a letter to Congress on Tuesday. "We know of no administrative actions that could, and therefore we have no plans that would, undo the massive damage to our healthcare system that would be caused by an adverse decision," Burwell wrote. Burwell had previously declined to say whether the administration has a backup plan if the Court strikes down subsidies for millions of people under the law in the case of King v. Burwell, set for arguments March 4.