* Both sides plan Washington rallies
* Will seize on hearings to bolster campaign rhetoric
* Protests reflect public divisions on the issue
By David Morgan
WASHINGTON, March 14 (Reuters) - The fate of President Barack Obama's healthcare overhaul will be debated at the Supreme Court this month, reviving controversy over his signature domestic policy achievement in a year when Americans vote on whether to give him a second term.
Democrats and Republicans, backers and foes, are spoiling for a battle ahead of the court's six hours of hearings on March 26-28, the most time given to a single topic in 44 years.
While the court's nine justices will rule on the legal issues, probably before July, political rivals and interest groups are seizing the moment to shape public opinion in the run-up to presidential and congressional elections on Nov. 6.
The public relations battle pits the Democratic Obama administration and its allies against a counter-force of Republican lawmakers, conservative pundits, Tea Party activists opposed to big government, and business leaders.
Opinion polls show Americans as divided as ever - with 41 to 47 percent favoring the law and 40 to 45 percent disapproving of it. As might be expected, a majority of Democrats surveyed like it; a majority of Republicans don't.
Union members, mainline religious activists and other advocates of Obama's healthcare law will hold demonstrations near the courthouse on Capitol Hill, where Republicans including Tea Party activists plan rival rallies.
"The larger healthcare reform community is going to be out in force with a simple message: don't take away our healthcare," said Ethan Rome, who heads a coalition of progressive groups and labor unions called Health Care for America Now that has been waging a grass-roots campaign for reform since 2008.
Not to be outdone, Republicans are planning their own assault, including attack videos aimed at voters in battleground states and symbolic legislative action in Congress, on an issue they believe will resonate with key constituencies in the election campaign.
"This is a gift that keeps on giving, politically," said Sean Spicer, the Republican National Committee spokesman. "There'll be a fully coordinated effort targeting families, business owners, you name it."
The White House plans to join the fray with what it calls a public education campaign on healthcare reform, an issue the Obama camp has long seen as resonating with women voters who could prove key in the November election.
Aware of the issue's divisiveness, Obama appears set on leaving the public promotional task largely to lieutenants who will crisscross the country for a week of events culminating with the law's second anniversary on March 23.
Health and Human Services Secretary Kathleen Sebelius will lead the charge while Obama appears focused instead on economic issues, jobs and gasoline prices.
For Obama, the healthcare issue could pose serious risks. An aggressive push by the president might help Republicans stir public dissatisfaction about the law just as the high court begins its deliberations.
"He has to make a calculation about whether the law is better served by him not talking about it, than by his talking about it," said Dr. David Blumenthal, a reform advocate who helped lead the administration's healthcare team until 2011.
"It may be the better part of valor to keep healthcare below the radar screen and campaign on economics and the do-nothing Congress," he said.
The 2010 Patient Protection and Affordable Care Act, the most sweeping social legislation in a generation, is intended to extend coverage to more than 30 million uninsured Americans and help rein in costs.
More than half the 50 states, 26 to be precise, and a business group are challenging the law before the Supreme Court, charging that its individual mandate requiring most adults to buy private insurance, and its dramatic expansion of the joint federal-state Medicaid program for the poor, run afoul of the constitutional limits on federal power.
Most of the law's benefits don't kick in until 2014, leaving a vacuum that Republicans have exploited by casting reform as a new $1 trillion expansion of big government that has failed to lower costs or improve access for working families.
The administration has spent months keeping up a steady drum beat of speeches, reports and op-ed articles promoting benefits that millions of Americans already are experiencing, including a ban against coverage denial based on pre-existing conditions and lifetime coverage limits.
Republicans say internal polling shows stark opposition to reform in major electoral battleground states and among powerful constituencies including the elderly, working families and small business owners.
Republican leaders are so confident of their control over the healthcare reform message that they boast of being willing to finance television advertisements for Democratic candidates who want to take credit for the reform law.
"If the president cut an ad saying, 'I want to remind you that I passed Obamacare,' I think we would highly consider paying for that ad," said Spicer. (Editing by Howard Goller and Xavier Briand)