WASHINGTON — President Barack Obama on Tuesday declared his health care law a firmly established "reality" of American life even as the legality of one of its key elements awaits a decision by the Supreme Court.
"This is now part of the fabric of how we care for one another," Obama said of the law, one of his most prized domestic policy accomplishments.
For the second day in a row, Obama mounted a stout defense of a law that remains unpopular with the public and under legal challenge but that has contributed to 14.75 million adults gaining coverage since its health care exchanges began signing up people in 2013.
Obama's remarks, made at the annual Catholic Health Association Conference in Washington, amounted to a political argument for the law just weeks before the high court is expected to render its decision in a case that could wipe out insurance for millions of Americans.
Obama poked fun at opponents for issuing "unending Chicken Little warnings" about what would go wrong under his health care program.
"The critics stubbornly ignore reality," he said.
Anticipating the president's speech, Senate Majority Leader Mitch McConnell, R-Ky., said it was Obama who was "jousting with reality again."
"I imagine the families threatened with double-digit premium increases would beg to differ, as would the millions of families who received cancellation notices for the plans they had and wanted to keep," McConnell said. His office issued an email citing news accounts about surging health care costs, potential rate hikes and cancelled health plans.
At issue in the Supreme Court case is whether Congress authorized federal subsidy payments for health care coverage regardless of where people live, or only for residents of states that created their own insurance marketplaces. In the other states, residents can buy insurance through a federally run marketplace.
Nearly 6.4 million low- and moderate-income Americans could lose coverage if the court rules people who enrolled through the federal site weren't eligible for the subsidies.
The decision rests on the court's interpretation of a short phrase in the voluminous law. But Obama, wielding statistics and personal anecdotes, made a case that the law is so established that it has woven itself into the health care system.
"Five years in, what we are talking about is no longer just a law, it's no longer just a theory. It isn't even about the Affordable Care Act or Obamacare. This isn't about myths or rumors that folks try to sustain," he said.
"There is a reality that people on the ground day to day are experiencing."
Obama was speaking to a friendly audience. The Catholic Health Association split with the U.S. Roman Catholic bishops to support the Obama administration in 2013 in shaping a compromise over the law's birth control coverage. Sister Carol Keehan, the association's president and CEO, introduced Obama, saying the Affordable Care Act "took the first step toward guaranteeing health care for everyone in our great nation."
While the president highlighted the accomplishments of the health law, its adoption has not been without flaws. The initial sign up period was marred by a faulty web site, and a report Tuesday from a government watchdog agency found new problems verifying tax credit claims.
The Treasury Inspector General for Tax Administration released an audit that found the Internal Revenue Service did not get the required information on 1.7 million households in a timely manner from Department of Health and Human Services. As a result, the audit said, the IRS was unable to verify that people claiming health insurance tax credits on their tax returns had in fact purchased coverage.
Moreover, public opinion remains mixed. A recent Washington Post-ABC poll found that a majority of Americans continue to oppose the law. But the poll, conducted at the end of May, also found that 55 percent of those surveyed don't want the Supreme Court to block any subsidies.
Should the court rule against Obama, Congressional Republicans say they are working toward legislation to temporarily replace the subsidies for people losing them, probably until sometime in 2017, when they hope a Republican will be president.
Then, they hope to repeal the entire law and replace it with one with fewer requirements for coverage.
Sen. John Barrasso, R-Wyo., said Tuesday that House and Senate lawmakers were "very close" to a bill creating temporary tax credits that they would unveil after the court's decision. It would likely erase some of the law's requirements, such as for employer coverage of workers, which means it would almost certainly be vetoed should it reach Obama.
Republicans have proposed several plans for addressing the Supreme Court case, but have not united behind one.
Associated Press writers Ricardo Alonso-Zaldivar and Alan Fram contributed to this article.