Washington - Contending that President Barack Obama exceeded his constitutional powers in the way he has enforced the 2010 health care law, a sharply divided US House of Representatives approved a Republican plan to file an election-season lawsuit against him.
Democrats say the lawsuit is a campaign-year stunt designed to draw conservative voters to the polls in congressional elections in November.
They also say it may be a prelude to an effort to impeach Obama, a suggestion which top Republicans say is groundless.
Republicans say Obama has gone too far in selectively enforcing parts of the health care overhaul, the signature legislation of his presidency, such as by delaying the requirement that many employers provide health insurance for their workers.
They say they are protecting the Constitution's division of powers. Republicans have not laid out a timetable for actually filing the suit.
The House vote ON Wednesday was 225 to 201. No Democrats voted for the plan.
Speculation about impeachment of Obama has been popular among conservative activists and some lawmakers, despite House Speaker John Boehner's dismissal of the idea.
Democrats have capitaliSed on the speculation, sending fund-raising pleas to their own supporters warning that Republicans are out to impeach Obama and ruin his presidency.
Republicans, who are expected to keep their House majority after November's elections and hope to gain control of the Senate, say Obama has enforced laws as he wants to, dangerously shifting power to the presidency from Congress.
Obama said the vote to file a lawsuit is taking away from time the lawmakers could be spending on issues important to the American people.
He described the measure as a "political stunt" and said he took actions on his own because Congress isn't doing anything to help him.
Every Republican lawmaker opposed Obama's health care overhaul.
Republicans say Obama has illegally changed the law by using executive actions that don't require Congress approval. The White House and Democrats say he's acted legally and within his powers as chief executive.
Republicans say there are other examples of Obama exceeding his powers. These include failing to notify Congress in advance when he traded five Taliban members held at the prison at Guantanamo Bay, Cuba, for the captive Army Sergeant Bowe Bergdahl, and unilaterally preventing the deportation of some children who illegally immigrated to the US.
Despite these accusations, Republicans intend to limit their lawsuit to a narrow claim: that Obama has failed to faithfully carry out the health care law that, according to polls, remains poorly received by the public.
Federal courts are often reluctant to intervene in disputes between the executive and legislative branches. For the suit to survive, Republicans would have to prove that the House had been injured by Obama's actions. And even if the lawsuit was heard, it is unclear whether it could be decided while Obama was still in office.
Timothy K Lewis, a former judge in the 3rd US Circuit Court of Appeals, said that with appeals, it would take at least one-and-a-half to two years for the suit to wind through the federal judicial system.
Obama leaves office in January 2017.
Congressional lawsuits against presidents are rare. In 2008, a federal judge backed a suit by Democrats who then controlled the House and were trying to force the Bush administration to honour House subpoenas of senior White House officials. Though the House won the first round in court, that decision was under appeal when a settlement was reached and the lawsuit was dropped.
On Wednesday, neither side wasted time in using the fight to mine campaign contributions and line up support for their candidates.