The US Supreme Court has finished the first day of a landmark hearing on the constitutionality of President Barack Obama's signature healthcare reform.
Twenty-six US states have brought the Republican-led challenge to the administration's 2010 law.
The act expands health coverage to 32 million Americans, but critics say its requirement that people buy insurance intrudes on civil liberties.
A ruling is expected by late June - in the thick of the election season.
Yesterday's hearing focused on whether the judges actually had the power to rule on the case.
The Washington DC court, which holds about 400 people, was packed with lawmakers, senior Obama administration officials and members of the public.
People had been camping outside the white marble building since Friday.
The most eagerly anticipated day is today, when the judges will hear arguments on the constitutionality of the individual insurance requirement.