Washington (CNN)Two of the most complex issues in American politics -- gun control and gerrymandering -- are colliding this week in Washington.
How gerrymandering keeps Congress from passing gun control laws
The Sunday night shooting in Las Vegas that left 59 dead and hundreds more injured has restarted a debate over whether Congress should impose stricter gun laws, particularly around background checks for gun buyers and the sale of semi-automatic firearms.
But Democrats pushing for those laws have run into the same roadblocks that stymied former President Barack Obama in the wake of the Sandy Hook Elementary shooting in 2012: The National Rifle Association's overwhelming influence in Republican strongholds.
That power comes largely as a result of the extreme partisan makeup of most of the nation's congressional districts: The primary is a more serious threat to most incumbents than the general election. And in Republican primaries, the NRA's endorsement and advertising dollars carry huge weight.
"It gives the NRA leadership an enormous outsized influence on these members," said Jason Kander, an Army National Guard veteran and the former Democratic Missouri secretary of state. "They're more afraid of losing a primary than they are more people losing their lives."
A major underpinning of the polarization of American politics over the last two decades has been the disappearance of "swing seats." The Cook Political Report's "partisan voter index" -- which measures how each congressional district performs at the congressional level compared to the nation as a whole -- scored 164 districts within five points of the average in 1997. But by this year, that number had dropped to 72 -- a 56% decline meaning that fewer than one-in-six House seats are naturally competitive.
That's where another issue -- gerrymandering, the use of partisanship in drawing the boundaries of congressional and state legislative districts -- comes in.
The Supreme Court heard a Wisconsin case Tuesday that could lead to new rules that would result in more competitive congressional maps.
Such a ruling, gun control advocates hope, would spur lawmakers of both parties representing those districts to court voters in the center, rather than playing to partisan extremes.
Some forms of gun control are overwhelmingly popular. This spring, the Pew Research Center found that 83% said they consider gun violence in the US a big problem -- including 50% who called it "a very big problem." Sixty-eight percent told Pew they favor a ban on assault-style weapons, while 64% favor banning high-capacity magazines that hold more than 10 rounds. Majorities also favor background checks for private and gun show sales.
The popularity of those measures doesn't matter, though, because majority Republicans in the House and Senate -- many from rural states where gun ownership and hunting is central to their culture and the NRA's membership is powerful -- are more threatened by competitive primaries, where the NRA's endorsement of a challenger who has opposed all forms of gun control would pose a grave threat.
"This is one of the few issues where gerrymandering plays a large role," said Jon Soltz, the chairman of VoteVets, a progressive group that backs Democratic veterans in House and Senate races.
The inability of Congress to pass stricter gun laws isn't just because of Republicans.
In 2013, five Democrats, including North Dakota Sen. Heidi Heitkamp, sank a measure written by Sens. Joe Manchin, D-West Virginia, and Pat Toomey, R-Pennyslvania, to expand background checks.
Since then, Democrats have watched as President Donald Trump has risen to power in part by relying on the Republican base -- emphasizing issues like curbing immigration, limiting LGBT rights and more that energize that base and keep the party's congressional leaders on board with his agenda, even when those issues are unpopular with the broader electorate.
If Trump was a Democrat, "He would attack the NRA, because that's what people are afraid of, and he would tie them to something that's anti-American, like the Confederacy or Russia. And he would do it very aggressively with his own voice," Soltz said.
Some Democrats have shed the caution with which they approached the 2013 gun control debate and are taking more aggressive stances.
Connecticut Sen. Chris Murphy said Congress should "get off its ass." Massachusetts Rep. Seth Moulton refused to join Trump's moment of silence for Las Vegas victims, saying that "it's time for action."
The Progressive Change Campaign Committee said this week it would send fundraising emails to its list of 1 million members on behalf of politicians who demand stricter gun laws. PCCC co-founder Adam Green said in an email to the group's supporters that the effort is to "reward those brave political leaders who go beyond kind thoughts and prayers -- and who demand action on guns."
But Republicans resisted those calls. Kentucky Gov. Matt Bevin tweeted, "to all those political opportunists who are seizing on the tragedy in Las Vegas to call for more gun regs...You can't regulate evil..."
Still, the House did opt to shelve a bill this week that would have loosened restrictions on purchasing gun silencers.
White House press secretary Sarah Sanders said Monday it wasn't the time to talk gun control.
"I think that there will be, certainly, time for that policy discussion to take place. But that's not the place that we're in at this moment," she said.