Republicans said the legal action pushed by House Speaker John Boehner, R-Ohio, focusing on Obama's implementation of his prized health-care overhaul, was designed to prevent a further presidential power grab and his unilateral decisions on how to enforce laws.
"I feel a keen responsibility to preserve and maintain the balance of power laid out in the Constitution," Chaffetz said. "Ultimately, if successful, this action will restrain excesses by future presidents of both parties."
Republicans also scoffed at Democratic claims that the lawsuit would be a waste of taxpayers' money.
"What price do you place on the continuation of our system of checks and balances? What price do you put on the Constitution of the United States?" asked Rep. Candice Miller, R-Mich. "My answer to each is 'priceless.'"
Democrats said the lawsuit would go nowhere and was designed only to encourage conservatives to vote in November's congressional elections. They also warned repeatedly that it could be a precursor of a more drastic GOP effort. Said Rep. Louise Slaughter, D-N.Y.: "The lawsuit is a drumbeat pushing members of the Republican Party to impeachment."
In fact, Democrats already are using that argument to mine campaign contributions. In their latest appeal, House Democrats emailed a fundraising solicitation even as debate was underway, saying, "Republicans have said this lawsuit has 'opened the door' to impeachment." The appeal asked for support for Democrats who "will finally put a stop to the tea party crazies and get President Obama's back."
Some prominent conservatives, including former Republican vice presidential candidate Sarah Palin, have called for Obama's impeachment, and some House GOP lawmakers have not ruled it out. Boehner has said he has no such plans and has called Democratic impeachment talk a "scam" to raise money.
"Impeachment is off the table. Why hasn't the speaker said that," House Minority Leader Nancy Pelosi, D-Calif., said.
On the road in Kansas City, Missouri, Obama cast the lawsuit as a "political stunt" and a distraction from the public's priorities.
"Every vote they're taking like that means a vote they're not taking to actually help you," he told his audience. He urged Republicans to "stop just hating all the time."
By suing Obama to demand that he carry out specific provisions of the 2010 health care overhaul, House Republicans would be asking the courts to hold him to the letter of a law that they all opposed and that the House has voted over 50 times to dismantle.
Republicans have accused Obama of exceeding his powers in a range of areas, saying he has enforced provisions he likes and ignored others.
These include not notifying Congress before releasing five Taliban members from the U.S. military prison at Guantanamo Bay, Cuba, in exchange for captive Army Sergeant Bowe Bergdahl, blocking the deportation of some children who are in the U.S. illegally and waiving some provisions of the No Child Left Behind education law.
Democrats say Obama has acted legally and simply has used the authority he has as chief executive.
Republicans have not laid out a timetable for actually filing the suit.
As for its chances of legal success, federal courts often are reluctant to intervene in disputes between the executive and legislative branches. For the suit to survive, the GOP first 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 still was in office.
Timothy K. Lewis, a former judge in the 3rd U.S. Circuit Court of Appeals who was nominated by former President George H.W. Bush, 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.
Republicans have particularly objected that Obama twice has delayed the law's so-called employer mandate. The provision requires companies with 50 or more employees working at least 30 hours weekly to offer health care coverage or pay fines, while businesses with fewer than 50 workers are exempt.
The requirement initially was to take effect this year. Now companies with 50 to 99 employees have until 2016 to comply, while bigger companies have until next year.
Democrats warned that the lawsuit could cost taxpayers millions of dollars. Republicans provided no specifics about the potential price tag, but the measure would allow House attorneys to hire outside lawyers and require quarterly public reports on expenditures.