We can work backward to assess the extent of the influence of the National Rifle Association on blocking gun legislation.

In 2013, President Barack Obama’s push to introduce modest changes to the nation’s gun laws collapsed in the Senate, done in by a filibuster that had the support of four Democrats and 41 Republicans. The Republicans were voting with the rest of their party: Only four Republicans in the Democratic-controlled body voted to end the filibuster. Three were from states that were then blue. The other was Sen. John McCain (R-Ariz.).

That the legislation would not have gone far in the House is beside the point for our purposes here. Senators don’t enjoy the same level of anonymity that members of the House do, and it was those senators who upheld the filibuster who got the credit (or blame) for killing a compromise that would have expanded background checks in the wake of the massacre at Sandy Hook Elementary School the previous December.

One thing more than any other powers the decision-making process for senators on controversial issues like this: Will it hurt my chances for reelection? That’s why those four Democrats decided to uphold the filibuster on the legislation. They represented red states and clearly saw the vote as helping to preserve their future electoral chances. (Two were up in 2014; both lost anyway.)

The Republicans were doing the same thing. Views of gun laws are deeply polarized and growing more polarized each year, as our Chris Ingraham noted on Monday. Republican legislators are often making the safer bet that opposing new laws regulating guns won’t hurt them politically.

If they start to think about wandering, though, there’s that bogeyman lurking in the Capitol’s corridors. That’s the NRA, with an outsize reputation in American politics as a political juggernaut that’s got Congress tight in its grip.

Republicans are always concerned about upcoming primaries, during which the electorate tends to be more conservative — and therefore less likely to respond well to a Republican who goes against the party line on guns. But that heresy is especially worrisome, since it could get the NRA to weigh in on behalf of a primary challenger.

Consider what happened to Richard Lugar, senator for Indiana until he lost his primary in 2012. Lugar went into that cycle as an incumbent who seemed likely to beat his challengers, including tea-party-aligned Richard Mourdock.

Lugar had an F grade from the NRA; Mourdock had an A. The NRA endorsed Mourdock in early March.

Early in April, Lugar led Mourdock by seven points, with many voters undecided. A month later, Mourdock led by 10, a function, the National Journal wrote, of outside groups “spending big bucks on TV ad buys and mail drops” for both candidates. Outside groups like the NRA. Mourdock won that primary. It was the incumbent’s nightmare come true.

A review of Senate primaries from 2010 on, though, indicates that the Lugar-Mourdock race is the only one in which the NRA weighed in on behalf of a Republican Senate challenger to oust an incumbent. There are enough qualifiers in that sentence to suggest that the pool of contests at issue is small — we reviewed 19 GOP senate primary contests, focused on hard-fought races — but it’s still worth noting.

In most cases, the NRA didn’t even grade the candidates for the primary, according to archives at the NRA Political Victory Fund website. In a number of other races, it didn’t endorse.

The exceptions:

  • 2012, Arizona. The NRA backed Jeff Flake (A grade) over Wil Cardon (A grade based on a questionnaire). Winner: Flake. He never led by fewer than 20 points in polling.
  • 2012, Indiana. As above.
  • 2014, Kentucky. The NRA backed incumbent Sen. Mitch McConnell (A+) over challenger Matt Bevin (A, questionnaire). Winner: McConnell. McConnell also consistently led by double-digits in polling.
  • 2014, Mississippi. The NRA backed incumbent Sen. Thad Cochran (A+) over challenger Chris McDaniel (A). Winner: Cochran.

Notice that, save Mourdock, the NRA’s endorsements were for two incumbents and two clear favorites (with McConnell falling into both categories). This is common for endorsements: Endorse the guy who’s probably going to win and you can try to take some credit for that victory after the fact.

Cochran’s an interesting case, though. He actually came in second in the first round of voting that year; had there been no runoff, he would actually have lost. In the runoff, thanks in part to Democrats in the state preferring him to McDaniel, Cochran emerged victorious by a narrow margin. But consider what happened: the NRA backed an establishment candidate who got over the finish line only thanks to primary rules that demanded the winner earn a majority of support. (McDaniel came about 1,700 votes shy of winning outright in the first round.)

What’s articulated above is not a track record of the NRA picking and choosing who will be the Republican candidates for the Senate. Especially when you consider what happened to Mourdock after the primary. Lugar’s race was complicated by being a moderate in a partisan election year and having spent a lot of time out of state. While Mourdock benefited from his opponent’s flaws in the primary, he was undone by his own in the general after he said that a pregnancy that results from a rape was “something that God intended to happen.”

If the NRA gets credit for Mourdock winning by 20 points in the primary, it gets the blame for his losing by six points in the general.

The NRA’s leverage is much more extensive than its endorsement, of course. Of the races we looked at, no candidate had an NRA grade lower than A-, save Lugar. The NRA’s position is now Republican orthodoxy, as mentioned above, and Republicans are tacitly expected to adhere to it. The threat of the NRA weighing in on a House race or a mayor’s race — a smaller race where its influence and money can play a bigger role — can be enough to influence the outcome.

For Republican senators, though, any fear of bucking the NRA is not borne out by the organization’s track record. It did take out one incumbent it disliked, an incumbent who was running against a tea party conservative in the same year that tea party conservative Todd Akin won the party’s primary in Missouri without the NRA weighing in. (He, too, lost after making poorly received comments about rape. It was a weird year.)

Put another way: The NRA hasn’t proven that a relatively popular Republican who votes for moderate gun control measures will actually face ouster from the Senate. We’ll note, too, that the Republican orthodoxy on the issue isn’t uniform. As we noted on Monday, even a quarter of Trump supporters back some new gun restrictions; more than three-quarters back new background checks.

The NRA’s greatest weapon is the perception that it’s a great weapon in electoral politics. As far as the Senate is concerned, that’s unproven.