WASHINGTON — House Republicans, stung by the Supreme Court decision upholding President Barack Obama's health care overhaul, are seizing on one wrinkle to bolster their election-year case for repeal — the court's judgment that the penalty for failing to get insurance is a tax.

The House has voted more than 30 times to scrap, defund or undercut the law since Obama signed it in March 2010, political moves that went nowhere in the Democratic-controlled Senate. Republican opponents cast the law as government overreach, socialized medicine and an unaffordable approach to the nation's system of health care.

Two weeks after the conservative-led court's ruling, the House GOP leadership pushed for another symbolic repeal vote on Wednesday with a fresh argument. Chief Justice John Roberts wrote in his majority opinion that the law was constitutional because it imposes a tax — not a penalty — on people who refuse to buy insurance. Republicans who repeatedly pressed for repeal said a "yes" vote would not only overturn the law but spare some 20 million Americans from an unnecessary tax.