The Senate voted this afternoon on the Manchin-Toomey bipartisan compromise amendment on background checks for weapon purchases, and the result was no surprise. The measure got 54 votes, six short of the total needed for an amendment to be tacked onto the existing Democratic bill. While the Senate will go on talking about the issue, this vote closes the chapter on the four-month-long push for gun control that was launched by President Obama after the Newtown massacre. The concept pushed by moderate West Virginia Democrat Joe Manchin and conservative Pennsylvania Republican Pat Toomey was the only possible addition to the roster of existing gun laws that had a prayer of becoming law. But if even this idea couldn’t be passed in the Democrat-run Senate, it’s self-evident that there is no possible proposal that could be agreed upon by both houses of Congress.

That means the National Rifle Association, which vowed to fight to the last against even a moderate expansion of background checks, let alone a ban on assault weapons or large ammunition clips that Democrats want, will have a valid claim to be the big winner of this legislative battle. But they need to make room in the winner’s circle for their arch foe, President Obama. By convincing all but four of the Senate Republican caucus to oppose Manchin-Toomey, the NRA spiked an inoffensive measure that could have given the GOP cover against charges that it obstructed any movement on guns after Newtown. That’s a gift that President Obama, who is hoping to grab back control of Congress next year, will gratefully accept.

It is true that, as I wrote yesterday, liberals like Obama deserve some of the credit for helping convince conservatives to stay away from Manchin-Toomey. By making it clear that they would never stop pushing for weapons bans and other efforts that can be construed as an attack on the Second Amendment, Democrats provided useful ammunition to an NRA campaign that treated any measure, no matter how reasonable, as the thin edge of the wedge toward infringement of gun rights. It was this belief that lent weight to the efforts of the lobby and its allies to convince Republicans that the benefits of backing Manchin-Toomey wouldn’t be worth the electoral risk it represented, especially in pro-gun red states.

But the Republican decision not to embrace Manchin-Toomey is a strategic mistake that won’t help them next year.

While the NRA is right to assert that Manchin-Toomey wouldn’t have ended the push for gun control, it would have effectively shelved the issue until a new Congress takes office in January 2015. And it would have enabled Republicans to say they had protected Second Amendment rights while also giving the lie to any Democratic assertion that they had obstructed a post-Newtown consensus about doing something about guns.

Will this make a crucial difference in November 2014? We can’t know yet, and it should be admitted that the NRA and its backers have reason to claim that no Republican will be defeated in an otherwise red state because they opposed an assault weapons ban or even by closing the gun show loophole on background checks that Manchin-Toomey would have achieved. The midterm electorate may resemble that of 2010 more than 2012, and the large number of vulnerable or open Democratic Senate seats also tilts the math in the GOP’s favor.

But Republicans should understand that by stonewalling a background checks law, they have handed the Democrats a cudgel with which they will be beaten relentlessly for the next year and a half. The GOP can complain all it wants about media bias, the exploitation of the Newtown victims by the president and the fact that none of the proposed new gun laws would have prevented another Newtown. The use of the victims of the Newtown victim families — as President Obama did again this afternoon after the vote — may seem exploitive to Republicans but it is also the sort of thing that cannot be directly answered by gun control opponents.

Instead of taking the air out of the Democratic balloon, they’ve re-inflated it. Their assumption that there will be no political cost to this decision may be a mistake. If 2014 turns out to be as dismal as 2012, Republicans may look back on this day and realize that they’ve made an unforced error.