A Justice Department spokeswoman said it decided against asking the full 11th U.S. Circuit Court of Appeals to review the August ruling by a three-judge panel of the court that found the requirement unconstitutional.
The decision not to seek review by the full appeals court will likely speed consideration of the matter by the high court in its 2011-12 term that begins next week. A ruling could come by late June, in the middle of the presidential campaign.
The Supreme Court has long been expected to have the final word on the legality of the individual mandate, a cornerstone of the Patient Protection and Affordable Care Act. A big uncertainty has been over when the court would decide the issue.
The law's fate before the nine-member court, closely divided with a conservative majority and four liberals, could come down to two Republican appointees, Chief Justice John Roberts and Justice Anthony Kennedy, legal experts have said.
The law, adopted by Congress in 2010 after a bruising battle, is expected to be a major political issue in the 2012 elections as President Obama seeks another four-year term. All the major Republican presidential candidates oppose it.
The president, a Democrat, has championed the individual mandate as a major accomplishment of his presidency and as a way to try to slow soaring health care costs while expanding coverage to the more than 30 million Americans without it.
The 11th Circuit Court of Appeals, based in Atlanta, ruled 2-1 last month in favor of 26 states and others that challenged the mandate for exceeding the power of Congress.
The Obama administration could have asked the full appeals court to reconsider its decision. But that could have pushed back any Supreme Court ruling to its 2012-13 term.
The 2-1 ruling conflicted with other appeals courts that have upheld the law or have rejected legal challenges, including a lawsuit by the state of Virginia, which was dismissed on procedural grounds.
A U.S. appeals court based in Cincinnati ruled Congress had the power to adopt the individual mandate, which takes effect in 2014. The losing side in that case, the Thomas More Law Center, already appealed to the Supreme Court in July.
The administration has steadfastly maintained its belief that the law will survive judicial scrutiny and be upheld by the Supreme Court. The states that have challenged the law have argued it went beyond Congress' authority to require coverage.