By James Vicini

WASHINGTON, Oct 2 (Reuters) – President Barack Obama’s sweeping healthcare overhaul will top the agenda in the new U.S. Supreme Court term that opens on Monday and could be the most momentous in decades.

Returning from its three-month recess, the nation’s highest court will confront legal challenges seeking to strike down Obama’s signature domestic policy achievement and a host of other charged issues in its 2011-12 term.

Other big cases pit privacy rights against new police tracking technology, involve jail strip searches and address a free-speech challenge by broadcasters to a U.S. government ban on nudity and blurted expletives on television.

More blockbuster cases on using race in college admissions, on Arizona’s tough law cracking down on illegal immigrants and on the rights of same-sex adoptive parents may be added to the docket later in the nine-month session.

“By June 2012, this term may prove to be among the most momentous in recent decades,” said Elizabeth Wydra, chief counsel at the liberal Washington-based Constitutional Accountability Center.

The healthcare law, Obama’s signature and most controversial domestic achievement that figures to be a prominent issue in the U.S. elections in November 2012, already has overshadowed the term’s other cases.

The law, which aims to provide more than 30 million uninsured Americans with medical coverage and to slow soaring costs, has wide ramifications for the health sector, affecting health insurers, drugmakers, device companies and hospitals.

“That of course would be the big enchilada,” said former U.S. Attorney General Dick Thornburgh in discussing the healthcare cases and the new Supreme Court term at a briefing sponsored by the conservative Washington Legal Foundation.

RULING COULD GO EITHER WAY

Legal experts said it was impossible to predict how the Supreme Court might rule on the healthcare law and said a decision could hinge on whether Congress exceeded its powers by requiring that Americans buy insurance or face a penalty.

“It will be a close case,” Jonathan Cohn, a former deputy assistant attorney general at the U.S. Justice Department in the George W. Bush administration, said at the briefing.

Other legal experts said any ruling by the nine-member court, closely divided with five conservatives and four liberals, could come down to Chief Justice John Roberts and Justice Anthony Kennedy, who often casts the decisive vote.

The epic healthcare legal battle, which began right after Obama signed the law in March 2010, moved to the Supreme Court on Sept. 28 when the Obama administration and 26 states opposed to the law filed separate appeals. [ID:S1E78R0ZI]

At issue was a U.S. appeals court ruling in Atlanta that struck down the law’s mandate that all Americans have health insurance, but upheld the rest of the law — the biggest healthcare overhaul in nearly 50 years.

The Obama administration defended the law as constitutional in its Supreme Court appeal.

Solicitor General Donald Verrilli, a former White House lawyer, said Congress adopted the law to address a national crisis that put health insurance costs beyond the reach of millions of Americans and denied coverage to millions more.

Paul Clement, a former Bush administration solicitor general who represents the states, said the law dramatically expands the federal government’s power.

He challenged the expansion of Medicaid, a federal-state partnership that provides health care to poor Americans, saying Congress unconstitutionally forced it on the states by threatening to withhold billions of dollars in funds.

MID-YEAR RULING LIKELY

After all the healthcare legal briefs have been filed by the currently scheduled date in late October, the Supreme Court is widely expected to officially agree to hear the dispute.

Arguments could be held in February or March, with a ruling likely by the end of June, in the midst of the presidential campaign in which Obama seeks another four-year term.

A ruling striking down the law would be a huge blow for Obama, legally and politically, months before the election.

A ruling upholding the law would represent vindication for Obama, but might make healthcare an even bigger issue for the Republican presidential candidates, all of whom oppose it.

In upcoming arguments, the top court on Nov. 8 considers privacy rights and new technology in a case on whether police need a warrant to use a global positioning system device to track a suspect’s movements.

The court in January is expected to hear a free-speech challenge to the Federal Communications Commission’s indecency policy that subjects broadcasters to fines for showing nudity or airing a single expletive blurted on a live television show.

The last term that ended in June produced business wins.

The court rejected the largest sex-discrimination lawsuit in U.S. history by female workers at giant retailer Wal-Mart Inc (WMT.N), ruled for telecommunications firm AT&T Inc (T.N) and ended a global warming lawsuit against utilities.

Robin Conrad, head of the U.S. Chamber of Commerce’s legal arm, told a briefing that fewer business cases were on the docket now, compared with the past two years. She said there were fewer challenges to state laws and hardly any labor employment disputes. (Reporting by James Vicini; Editing by Xavier Briand)