Let's say you work for the NRA. You faced a semi-close call in early 2013, in the wake of the Sandy Hook shooting. For the first time in half a generation, a gun control measure got a vote—a watery version of enhanced background checks—but four Democrats and nearly every Republican opposed it, allowing it to be sunk by a filibuster. By now you've got a pretty good idea of which party to back in 2014. And really, when November comes, are you going to be tempted to bail out Mark Pryor by endorsing him over Tom Cotton? Of course you're not.

So how hard are you laughing at the blockade of Vivek Murthy's nomination to be surgeon general? It was a classic drive-by shooting, an early push by the NRA that escaped the attention of the media until the target was beyond help. Reports Lisa Mascaro:

Democratic leaders in the Senate have begun surveying senators to determine whether there is enough support to save the troubled nomination. Few Republicans are expected to back Murthy, and as many as eight Democrats also could be opposed.

"We don't expect a vote to happen," a Senate aide said.

That means that at least three Democrats who were comfortable supporting Manchin-Toomey, plus probably Montana's new Sen. John Walsh, lost their sea legs after reading the NRA's Feb. 26 letter. Its brief against Murthy was based in large part on letters sent by the group he founded, Doctors for America, during the post-Sandy Hook debate. DFA had, for example, called on Congress to "remove the provision in the Affordable Care Act and other federal policies that prohibit physicians from documenting gun ownership." This was never going to happen—provisions like that had secured red-state-Democrat votes in the first place—but the NRA's Chris Cox argued that it was put there to "foster trust between gun owners and their physicians, ensuring that the information exchanged during an exam will not be used to curb the patient's rights."

The fear held by a Kay Hagan or Mary Landrieu was that a vote for Murthy would be a vote for "an assault weapons ban" or "government challenging your right to own a gun" is sort of legitimate. But it's not like either candidate was going to be spared; look at the ads the NRA ran against Barack Obama in 2012, after four years of no gun legislation. The gun lobby's influence has recently depended on soft power and fear of backlash, and the Murthy blockage restores that influence.