WASHINGTON — Few handicappers gave a band of Republican attorneys general much chance of success when they filed a constitutional challenge to President Obama’s health care law just minutes after it was signed on March 23, 2010. Some mocked them, while others largely ignored them.  But by the time the Supreme Court issued its landmark ruling to uphold the law on Thursday, the litigation hatched by conservative state legal officials like Bill McCollum, who was Florida’s attorney general, had attracted a legitimacy born of shifting scholarly opinion, early victories in strategically selected lower courts and popular discontent spurred by the Tea Party.  While they fell short of their ultimate goal, they got much farther than almost anyone had predicted, and can claim significant victories — both legal and political. The intellectual underpinning of the litigation had always been the argument that the health care law’s individual insurance mandate was an unconstitutional use of Congress’s authority to regulate commerce. On that score, the attorneys general won, with Chief Justice John G. Roberts Jr. the deciding vote.  “Well, at least it’s clear that they can’t order you to buy broccoli,” Mr. McCollum said, a final nod to the vegetable that played a central role in the plaintiffs’ case. “There are now very specific limits to the commerce clause.”  There were other upsides for conservatives in the 5-to-4 ruling. The attorneys general gained flexibility for their states in deciding whether to help pay for a coming Medicaid expansion, and the decision that the individual mandate constitutes a tax handed political ammunition to opponents of Mr. Obama and Democrats in Congress.  Moreover, the loose confederation of opponents — Republican officials from 26 states, party operatives, Federalist Society lawyers, conservative law professors, business leaders and Tea Party advocates — prompted a national conversation that helped keep health care near the top of the domestic agenda in both the 2010 and 2012 campaigns. And it prevented the Obama administration from gaining traction in promoting the benefits of the law.  “It’s kept them on defense,” said Henry McMaster, an early organizer of the group when he was South Carolina’s attorney general.  Randy E. Barnett, a libertarian Georgetown law professor who is among those credited with providing an intellectual framework for challenging the mandate, put it a different way. “Who would have thought that we could win while losing?” he asked.  The litigation arose out of conservative outrage in late 2009 over the so-called Cornhusker kickback, a $100 million Medicaid deal for Nebraska intended to win the vote of that state’s Democratic senator, Ben Nelson, for the plan. That legislative move riled Mr. McMaster into organizing conference calls with counterparts in other states. Public outcry and the threat of litigation helped kill the deal, with Mr. Nelson calling Mr. McMaster on New Year’s Eve to ask, “What do I need to do to call the dogs off?”  But even earlier, the attorneys general had shifted to a pet concern that Mr. McCollum had been raising relentlessly in the calls: the individual mandate.  In September 2009, Mr. McCollum, a former congressman with solid conservative credentials, was leafing through The Wall Street Journal when he noticed an opinion column by two former law partners, David B. Rivkin Jr. and Lee A. Casey. The headline was unequivocal: “Mandatory Insurance Is Unconstitutional.”  Many lawyers considered the premise frivolous. But after research by his chief deputy, Joe Jacquot, a former Senate Judiciary Committee aide who had helped manage Chief Justice Roberts’ confirmation, Mr. McCollum concluded that the lawyers had a compelling case.  Mr. McCollum provided not only the impetus for the lawsuit, but also the venue. He persuaded his colleagues that an early victory was crucial, and that the friendliest path would be through the Federal District Court in Pensacola, Fla., and then the United States Court of Appeals for the 11th Circuit in Atlanta.  In contrast to the partisan opposition from other corners, the Republican attorneys general pledged to talk only about the legal issues, Mr. McMaster said.  “We stressed that in our conference calls,” said Mr. McMaster, who like Mr. McCollum returned to practicing law after losing a primary election for governor in 2010. “This is all about the law, about the Constitution. Don’t let anybody in anybody’s office say anything ugly about the president or the Congress. Stay in your lane.”  But Drew Edmondson, who was the attorney general of Oklahoma and one of the few Democrats invited to join the conference calls, said he had perceived the agenda as “clearly political with a legal hook” — an effort driven partly by opposition to the Obama administration.  The attorneys general had hoped for a united front, but Kenneth T. Cuccinelli II, the Republican attorney general in Virginia, brought a federal lawsuit of his own in Richmond, challenging the mandate on the ground that it violated a states’ rights bill recently passed in the commonwealth with Tea Party backing.  Michael D. Shear contributed reporting.
An opposition case that was given little chance of succeeding ended up enlisting 26 states and securing some significant political and legal victories.