200px-Seal_of_the_United_States_Senate.svg_With this week’s bat­tle over gun con­trol leg­is­la­tion in the Sen­ate, I thought it worth­while to exam­ine it from a qual­i­ta­tive and quan­ti­ta­tive per­spec­tive. A total of 46 Sen­a­tors voted against clo­ture on the Manchin-​​Toomey back­ground check pro­posal, thus killing it with­out requir­ing any­one to actu­ally speak on the floor of the Sen­ate. This is exactly what many peo­ple expected to hap­pen, and why there were calls early in the year to require fil­i­bus­ter­ers to speak on the Sen­ate floor to pre­vent votes on bills.

I wrote this before Nate Silver’s sta­tis­ti­cal analy­sis was pub­lished yesterday.

In any case, the 46 Sen­a­tors con­sisted of 41 Repub­li­cans and five Democ­rats. Let’s start by look­ing at the four Democrats. 

Sen­a­tor Max Bau­cus (D-​​MT)

Bau­cus is up for reëlec­tion next year in a state in the West­ern Inte­rior, a region known for its attach­ment to firearms. Mon­tana ranks #3 in a 2001 Behav­ioral Risk Fac­tor Sur­veil­lance Sys­tem (BRFSS) sur­vey in terms of per-​​capita gun own­er­ship. It’s hardly sur­pris­ing that he would be reluc­tant to vote in favor of any forms of gun con­trol. After all Mon­tana is a state whose leg­is­la­ture passed a bill last month nul­li­fy­ing any fed­eral gun control.

While Demo­c­ra­tic Sen­a­tor Jon Tester man­aged to get reëlected last year against chal­lenger Denny Rehberg, Mon­tana remains a con­ser­v­a­tive state over­all. Big Sky Coun­try has a Cook Par­ti­san Vot­ing Index of R+7, plac­ing it on the right edge of states inclined to vote for a Demo­c­rat. Bau­cus had plenty of rea­son to avoid giv­ing ammu­ni­tion to his future gen­eral elec­tion opponent.

Sen­a­tor Mark Begich (D-​​AK)

Alaska and Mon­tana have much in com­mon, and every­thing that applies to Bau­cus applies to Begich. Alaska is #2 in the BRFSS sur­vey, though hasn’t yet passed any gun con­trol nul­li­fi­ca­tion bills. Nonethe­less, Begich has a dif­fi­cult road ahead of him; Alaska’s PVI of R+12 indi­cates a sig­nif­i­cantly higher degree of par­ti­san­ship there than Bau­cus sees in Mon­tana. Only the extra­or­di­nary sit­u­a­tion of a felony con­vic­tion led to the late Sen­a­tor Ted Stevens’s defeat, by a mere one per­cent­age point, in 2008.

Sen­a­tor Heidi Heitkamp (D-​​ND)

See a trend yet? North Dakota has much cul­ture in com­mon with Alaska and Mon­tana, and sits at #10 in the BRFSS study. Its R+10 PVI places it between the two in par­ti­san­ship. Unlike Bau­cus and Begich, though, Heitkamp was just elected last Novem­ber. She defeated Repub­li­can Rick Berg by just one per­cent­age point.

Sen­a­tor Mark Pryor (D-​​AR)

Pryor, like Bau­cus and Begich, is a Demo­c­rat in a red state who is seek­ing reëlec­tion in 2014. He has the largest PVI to over­come, since Arkansas is a ruby-​​red R+14, and the state is #6 in the BRFSS study. Nonethe­less, he is in the unusual posi­tion of being a red-​​state Demo­c­rat who had no Repub­li­can oppo­si­tion in his last election.

Sen­a­tor Harry Reid (D-​​NV)

Wait, what? Reid isn’t up for reëlec­tion, and more impor­tantly is the Sen­ate Major­ity Leader. What’s his excuse? It’s more a pro­ce­dural thing than any­thing else, because of his posi­tion. Nevada is well below aver­age in gun own­er­ship, despite the wild-​​west persona.

Next, let’s look at the red-​​state Democ­rats who voted in favor of cloture.

Sen­a­tor Kay Hagan (D-​​NC)

North Car­olina is a PVI R+3 state, #23 on the gun own­er­ship sur­vey, and Hagan beat incum­bent Sen­a­tor Eliz­a­beth Dole by a siz­able mar­gin in 2008. Her risk here was fairly low.

Sen­a­tor Mary Lan­drieu (D-​​LA)

This is a sur­prise. Louisiana is a PVI R+12 state with a par­tic­u­larly pow­er­ful love of firearms, as evi­denced by the recent con­sti­tu­tional amend­ment ban­ning most gun restric­tions, and the state’s rel­a­tively high rank of 13 on the gun own­er­ship sur­vey. Lan­drieu is also up for reëlec­tion next year, and is con­sid­ered one of the most vul­ner­a­ble Sen­a­tors in the 2014 elec­tion cycle. This was a seri­ously gutsy move on her part.

Sen­a­tor Mark Udall (D-​​CO)

Col­orado is a dif­fi­cult state to hand­i­cap. Its D+1 PVI sug­gests that Udall isn’t risk­ing much here, but Col­orado is also a West­ern Inte­rior state, and five of the six adja­cent states (six of seven if you include Ari­zona) are solidly red. Yet Col­orado is 33 on the gun own­er­ship sur­vey, sug­gest­ing this par­tic­u­lar vote isn’t any­where near as dan­ger­ous for Udall’s prospects as Landrieu’s is for hers.

What about Repub­li­cans who voted in favor of clo­ture? This is an inter­est­ing list, and one that hasn’t got­ten much press.

Sen­a­tor Susan Collins (R-​​ME)

No sur­prise here. Collins is par­tic­u­larly lib­eral by today’s Repub­li­can stan­dards. Despite her being up for reëlec­tion next year, Maine isn’t the sort of state where the NRA can swoop in and do much dam­age to an incum­bent Sen­a­tor. The small-​​community feel of the state blunts large PACs’ abil­ity to influ­ence statewide elec­tions. Collins is free to vote her con­science, and I expect her to con­tinue to be rewarded for doing so.

Sen­a­tor Mark Kirk (R-​​IL)

This is also not much of a sur­prise. Illi­nois is #44 on the gun own­er­ship sur­vey and a D+8 state. Kirk can ill afford to step far to the right. Even though he’s not up for reëlec­tion next year, this is a vote that could have last­ing reper­cus­sions in the Land of Lin­coln. Besides, he was a cospon­sor of the bill.

Sen­a­tor John McCain (R-​​AZ)

McCain’s vote is a sur­prise. Ari­zona has some of the least restric­tive gun laws in the nation, which has led the Grand Canyon state to be a lead­ing source for ille­gal weapons in Mex­ico. He is risk­ing a pri­mary chal­lenge in 2016, though he will be nearly 80 years old by then and may be plan­ning to retire.

Sen­a­tor Pat Toomey (R-​​PA)

While Pennsylvania’s D+1 PVI and rank of 34 on the gun own­er­ship sur­vey sug­gests that a yea vote makes sense here, Toomey has built a brand of extreme con­ser­vatism. This makes him vul­ner­a­ble to a pri­mary chal­lenge in 2016. For this rea­son, I would con­sider his yea vote nearly as sur­pris­ing as McCain’s. On the other hand, he cospon­sored the bill, so it’s not really a sur­prise in toto.

Were you sim­i­larly sur­prised by some of those votes? How would you cal­cu­late the effects of this par­tic­u­lar vote on the future makeup of the Senate?