(CNN) -- House Republicans are going forward with plans to sue President Barack Obama and will base their legal case on the sweeping health care law he championed and they despise.
Speaker John Boehner said the suit, which also highlights an ironic Obamacare twist, will follow the argument Obama violated the Constitution by circumventing Congress and alone delaying the law's requirement for businesses to provide coverage.
"In 2013, the President changed the health care law without a vote of Congress, effectively creating his own law by literally waiving the employer mandate and the penalties for failing to comply with it," Boehner said in a statement.
"That's not the way our system of government was designed to work. No president should have the power to make laws on his or her own," he added.
The Republican-led House is expected to vote on a resolution authorizing legal action against the President over Obamacare at the end of the month, just before lawmakers head home for August to campaign for midterm votes.
Boehner then is expected to hire attorneys to actually file the suit in federal court. But the timing of that is unclear.
The Rules Committee plans to hold a hearing on the matter with outside legal experts.
White House calls it a 'stunt'
The White House expressed disappointment in a statement, saying Boehner and Republicans are wasting time and taxpayer resources on a "political stunt."
"As the President said today, he is doing his job -- lawsuit or not -- and it's time Republicans in Congress did theirs," the statement said.
Obama defiantly challenged Republicans last week, saying he would continue to take steps he felt were necessary with or without the support of congressional Republicans.
"So sue me," he dared them.
House Democratic Leader Nancy Pelosi also dismissed the suit as a political "stunt."
The case magnifies a toxic partisan climate that has engulfed Congress and come to define Obama's relations with Republicans in general. Some arch-conservatives in the party want him impeached.
Boehner doesn't agree with such a step, but he's plowing ahead with an unusual legal challenge built around Republican claims Obama has abused his authority at the expense of the legislative process.
Boehner's staff has consulted experts and considered several options for the legal basis needed to make the case.
Another key area of contention was Obama's move in 2012 to defer deportations of children who enter the country illegally -- a hot button issue today with thousands of minors crossing the southern border unaccompanied. Also, environmental regulations and the Taliban prisoner exchange that freed Army Sgt. Bowe Bergdahl were criticized.
But a senior House Republican leadership aide said the health care case gives the House "the best chance of success in the courts."
So far, the House has passed two bills aimed at curbing executive orders. Neither has gone anywhere in the Democratic-controlled Senate.
Must prove harm
Many legal experts have already said any lawsuit of this kind would face challenges.
In order for it to be formally considered by the courts, House Republicans must prove that the chamber was somehow injured as an institution.
Obamacare has been a partisan flashpoint since it's passage in 2010 with no GOP support. The House has approved dozens of bills aiming to weaken or repeal it.
The Obama administration a year ago postponed a requirement that businesses with more than 50 workers provide their employees with health insurance. The so-called employer mandate now won't take effect until 2015.
Ironically, the same lawmakers pressing the lawsuit on Thursday actually voted on House legislation a year ago that would have delayed the mandate.
But pushing that measure through the Democratic-controlled Senate would have required debate, possibly other changes, and a likely delay just as the administration was gearing up to put the measure into practice.
Justifying the apparent contradiction of suing the President over taking action they actually supported initially, Republican aides said it is up to Congress to make those changes in law, not the President.
Another centerpiece of the initiative required individual Americans to obtain health insurance from Obamacare or on the private market, or face a possible fine. So far 9 million people have signed up for plans under the health law, the administration has said.
It's the signature domestic policy achievement of Obama's presidency so far and a rallying cry for Republicans, especially on the midterm campaign trail.
Earlier in the day, Boehner argued a suit wasn't simply a personal issue, but a move to defend Congress as an equal branch of government.
"It's not about Republicans versus Democrats. This is about the legislative branch that's being disadvantaged by the executive branch. And it's not about executive actions. Every president does executive orders," Boehner said.
Saying most presidents act lawfully, Boehner said Obama "is basically rewriting law to make it fit his own needs."
CNN's Dana Davidsen contributed to this report.