Because Congress failed to adopt a bipartisan deficit commission on its own, President Obama created one through executive order on Thursday. This comes as a disappointment to members of both parties who had endorsed the Conrad-Gregg bill: that proposal would have forced the Congress to vote on the commission’s recommendations, while the administration’s initiative does not.

The failure of Conrad-Gregg was surprising as well as troubling. By last December, the bill had garnered almost three dozen cosponsors across party lines and seemed to be gaining momentum. Although Senate minority leader Mitch McConnell had not formally signed on, he had made a number of favorable public statements. (Last May, for example, he proclaimed on the Senate floor that the Conrad-Gregg proposal was “the best way to address the crisis” and that it “would provide an expedited pathway for fixing these profound long-term challenges.”) And just days before the vote, President Obama endorsed the bill.

But it wasn’t enough. On January 26, the bill went down to defeat: 53 senators voted in favor, but it needed 60 to pass. Democrats assembled a solid majority of 37 votes, while Republicans could muster only 16. As has been widely reported, seven of the bill’s Republican cosponsors ended up voting against it; had they remained resolute, it would have passed. Reversing his earlier position, the minority leader also voted against the bill.

So what happened between December and January? Put simply, the forces within the conservative movement who oppose any and all tax increases mobilized against legislation that might have produced the long-sought grand bargain—significant entitlement reform coupled with additional revenues.

On December 9, Grover Norquist of Americans for Tax Reform sent a letter to Conrad and Gregg expressing his opposition to their proposal. “Despite the appearance of protection for taxpayers,” he wrote, “this commission would guarantee a net tax increase. … In order to make this commission acceptable from a taxpayer perspective, language must be included that explicitly removes tax increases and/or new taxes from commission consideration.” The substantial anti-tax coalition Norquist leads then swung into action with a steady drumbeat of op-eds and open letters to elected officials.