All elected United States federal officials, from the President of the United States of America, to Congress and the courts, as well as appointed officials in the Administration and the courts, must be held subject to the same legal requirements found in the Affordable Health Care Act that all other American citizens are to be held.
The federal officials that make laws are necessarily subject to the same laws. As such, a law that effects the general citizenry in the U.S. must also apply to those making the those laws. The U.S. Constitution does not allow the three branches of government immunity from its own laws.