"I can't really be more specific," said J. Mark Iwry, deputy assistant Treasury secretary for retirement and health policy, told a House health subcommittee looking into the decision to delay the mandate. "The decision was made in a very deliberate way, so it was obviously something that took into account an evolving body of evidence."
The Treasury and White House announced in a twin blog posts on July 2 that it would delay by one year, to 2015, the mandate in the Affordable Care Act that requires companies with the equivalent of 50 or more full-time workers to provide health coverage or pay fines.
The administration cited the concerns business leaders had about the mandate's complex reporting requirements, but critics of the law said the delay reflected the law's unworkability and political unpopularity.
House Republicans are holding votes on Wednesday to codify the employer mandate delay and then, in a separate bill, apply the same delay to the individual mandate requiring most Americans to acquire some form of health coverage.
GOP leaders say the Obama administration has put the interests of "big business" over ordinary Americans.
"Warren Buffett gets a break; Joe Six-pack doesn't," Rep. Kevin Brady, Texas Republican and chairman of the health panel.
Rep. Jim McDermott, Washington Democrat and ranking member on the panel, noted that 95 percent of companies with more than 50 full-time workers already offer insurance, and that companies in Massachusetts did not drop their employees' coverage when the state instituted similar health reforms several years before the formation of the federal health care law.
Mr. McDermott said that unlike the employer mandate, the individual mandate is a linchpin of Mr. Obama's overhaul.
Republicans' desire to help consumers with pre-existing health conditions, while repealing the mandates, will not work, he said.
Without the individual mandate, healthier Americans may shirk on buying insurance and leave only the sickest patients in the risk pool, he said, sending the insurance market into a "financial death spiral."