Blame the gun lobby. Blame Republicans. Blame a handful of skittish Democrats who gave the GOP cover. Blame the entire band of demagogues who killed the modest attempt to close loopholes in a law requiring background checks for guns.
Blame them, too, for jeopardizing President Obama's entire legislative agenda. That was the point, anyhow, right?
But don't call this good news for Obama's enemies, at least not yet, because under new rules of politics that are still being written, the victory could be Pyrrhic. In an era of voter empowerment and surprise, the GOP's opposition to a popular gun regulation could backfire.
An amendment aimed at salvaging the background check measure fell six votes short of the 60-vote threshold needed to move ahead in the Senate on Wednesday. It was the last remnant of a gun-regulation package that Obama proposed in the aftermath of the Sandy Hook Elementary School slaughter. "I will put everything I've got into this," Obama said at the time.
It wasn't nearly enough.
The defeat raises questions about Obama's ability to unify congressional Democrats and to mobilize supporters via his nascent Organizing for Action, a first-of-its-kind political machine controlled by the White House. The president will need party unity and grassroots muscle to battle the GOP on immigration, federal spending, climate change and other White House interests.
Coming into the week, Obama's agenda appeared to be at an important juncture — with guns, immigration, and deficit-reduction talks at various stages of progress. Winning an expansion of the background check, even as bolder gun measures failed, would have given Obama momentum to push the other two items.
Conversely, his rivals may now feel emboldened to block Obama's entire agenda. In their most cynical moments, Republican leaders privately cheer themselves with the fact that a president's approval rating usually suffers amid gridlock.
Obama's team took news of the defeat hard Wednesday, with some advisers predicting that gun regulation won't be revived. It is hard for them to explain the failure of a measure supported by 90 percent of the public without making the president appear weak.
"I can't understand it. I really can't," said Sen. Joe Manchin, D-W.Va., who tried to save the bill by joining with Republican Sen. Pat Toomey of Pennsylvania on an amendment.
David Axelrod, the president's top consultant, chastised a handful of Senate Democrats from conservative-leaning states who opposed Obama.
"Show some courage," Axelrod said on MSNBC. "Is it worth holding those jobs simply to sit there and be called a United States senator?"
In addition to Senate Republicans, of course, there were others to blame:
The GOP-controlled House. House Republicans, most of whom come from heavily conservative districts, were expected to reject any measure sent by the Senate. That made it almost impossible for Obama to keep Senate Democrats in line: Is it fair to demand that a senator risk his or her seat on a bill destined to die in the House?
The gun lobby. The National Rifle Association and other groups funded by the gun industry distorted the debate with false assertions and bullying. Among the worst offenders was the National Association for Gun Rights, which wrongly accused Republican congressmen of working with Obama to create a federal registry and confiscate guns.
Sen. Rand Paul. The likely GOP presidential candidate helped the NAGR raise money and knew of its lies, but refused to denounce them.
Obama deserves credit for trying. He lobbied lawmakers directly, traveled frequently, engaged families of the Sandy Hook victims, flexed the untested muscle of the OFA, and spoke eloquently about the need for gun regulation.
It's hard to overcome challenges that are inherent. While polls show broad support for background checks, they also show a deep distrust of Obama among conservative voters, particularly in red states. Democratic Sen. Mark Pryor's supporters will tell you the only thing more dangerous than backing gun control in Arkansas is backing Obama — on anything.
Also, the passions of gun-rights supporters are measurably greater than the intensity of gun-control advocates.
One senior Obama associate who works outside the White House said on condition of anonymity, "If we can't get it done four months after Sandy Hook, how are we going to get it done any time in the next four years?"
"This," the associate said, "is an unmitigated disaster."
That dim view is based on the old rules of politics. But what if new ones apply?
What if the fledgling OFA converts Obama's reelection machine to a million-member lobbying force? What if voters who support the Second Amendment and commonsense gun regulation get angry at Congress for ignoring them? What if these voters realize that the same social and technological forces that democratized 21st century media and commerce — as well as enabling revolutions in the Middle East — also empower individual Americans to change Congress?
What if Washington is surprised again? This town underestimated opposition to Obamacare in 2009 and to the Stop Online Piracy Act in 2012. The former ignited the tea party; the latter inspired a groundswell of online activism that killed a bill embraced by the Washington establishment.
One wonders if this is what a visibly angry Obama had on his mind Wednesday evening when he asked Americans to do what their president could not: Defeat the GOP and NRA. "To change Washington, you, the American people, are going to have to sustain some passion about this," said the man elected on a promise to change Washington.
Can gun safety to be the next SOPA? Is Obama's legacy toast? The answers — and power — lie with voters.
Correction: The original version of this post misidentified Organizing for Action.