Steve Ciccarelli of Annandale, Va., right, a proponent of the law, argued with Susan Clark, of Washington, about the ruling.

Chief Justice John Roberts surprised court watchers by voting to uphold the health care law.

Supporters celebrated after the Supreme Court upheld the law's constitutionality.

Presidential candidate Mitt Romney said the ruling showed that Republicans must defeat Barack Obama in November's election to overturn his health care overhaul.

President Barack Obama hailed the court's decision as a victory for people across America and urged opponents to rally behind the law.

Massachusetts Governor Deval Patrick watched President Obama on television after the ruling.

An artist's rendering showed Chief Justice John Roberts, center, speaking as the Supreme Court upheld the Affordable Care Act in a 5-4 ruling.

House Speaker John Boehner, an Ohio Republican, headed for the House chamber after the ruling.

House Minority Leader Nancy Pelosi smiled as she watched news of the court's ruling.

People celebrated in Chicago after President Barack Obama's health care law was upheld by the Supreme Court Thursday.

Senate Majority Leader Harry Reid, of Nevada, praised the justices for their decision.

Susan Clark, left, argued with another protester outside the Supreme Court on Thursday.

Protesters who opposed the act showed their dismay after the ruling was announced.

A protester held up a sign in the wake of the ruling.

Demonstrators prayed outside the court after the ruling.

Chicago area senior citizens went to a local cooling center to escape the summer heat and watch President Barack Obama's reaction.