The public remains divided on the merits of the law almost two years after President Obama signed it. Although many of its provisions don't take effect until 2014, the events are designed to shed light on parts of the law already benefiting voters.
It's a "significant teaching opportunity," said Ron Pollack, executive director of Families USA, a consumer advocacy group. "There has been so much mythology created, not least of which by the Republican candidates for president who simply repeat the mantra 'Repeal ObamaCare,' " he said.
The court is considering a challenge brought by 26 states, including Pennsylvania, to the law's requiring most American to buy health coverage and to its expansion of the Medicaid program for the poor.
Proponents plan to showcase rules in the law that allow dependents 26 and under to stay on their parents' health plans and that bar insurers from making coverage decisions against people with preexisting conditions.
One group opposing the law has already said it will bus people from as far as Michigan to rally against the measure. Americans for Prosperity, a nonprofit supporting Republican candidates and policies, will hold a "Hands Off My Health Care Rally" in a park near the court on the second day of arguments.
Nick Papas, a White House spokesman, declined to identify the groups that attended Wednesday's meeting or provide other details. The White House has hosted previous gatherings of supporters of the health law, Pollack said.
The groups were brought to the White House so the administration could get a full picture of the activities planned during the court arguments and the law's second anniversary March 23, said Ethan Rome, executive director of Health Care for America Now, an advocacy group.
Families USA, Rome's group, and others, including the United Methodist Church, already planned to hold events during the court arguments.
Brendan Steinhauser, director of federal and state campaigns for FreedomWorks, an activist group led by former House Majority Leader Dick Armey (R., Texas), is encouraging its members to go to Washington for rallies associated with the hearing and to visit lawmakers to "remind them of the importance of repealing ObamaCare."