As the Obama administration presses ahead with the health care law, officials are bracing for the possibility that a federal judge in Virginia will soon reject its central provision as unconstitutional and, in the worst case for the White House, halt its enforcement until higher courts can rule.

The judge, Henry E. Hudson of Federal District Court in Richmond, has promised to rule by the end of the year on the constitutionality of the law's requirement that most Americans obtain insurance, which takes effect in 2014.

For the complete New York Times story, click here.