In the wake of two deadly mass shootings, President Donald Trump succumbed to pressure from the gun lobby and declined to support legislation for stronger background checks on gun sales.

House Democrats are making big electoral gains in suburban areas, where voters overwhelmingly support greater restrictions on guns.

Recent polling from Politico/Morning Consult and the Republican Main Street Partnership show overwhelming support for stricter gun laws among Republican women, too — a huge warning sign for the GOP.

In one poll conducted after the El Paso and Dayton shootings, 71% of suburban voters and 64% of Republican women backed banning assault-style weapons.

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In the wake of two deadly mass shootings that killed 31 people and injured dozens of others in El Paso, Texas and Dayton, Ohio in early August, members of Congress from both parties pushed for new federal gun safety laws, including expanded background checks.

In the immediate aftermath of the shootings, President Donald Trump publicly expressed support for "strong background checks" and vowed "to act with urgent resolve."

Republican Senator Pat Toomey of Pennsylvania and Democratic Senator Joe Manchin of West Virginia both lobbied the president and his aides to support their bipartisan amendment that would extend mandatory federal background checks to private firearms sales at gun shows and transactions over the Internet.

But after prior mass shootings, like the deadly February 2018 shooting at Marjorie Stoneman Douglas high school in Florida, Trump had promised to "fight" the NRA on gun restrictions before eventually backing off and dropping the issue.

Read more: Trump stopped calling for 'very meaningful background checks' on guns after talking to the head of the NRA

In this case, a similar pattern played out: Trump expressed vague public support for more background checks, the powerful National Rifle Association called him and convinced him not to back any more gun safety measures, and Trump relented for the moment, virtually eliminating the chances of any bipartisan gun reform bill making it through Congress.

According to a recent report in The Atlantic, Trump and his daughter, White House advisor Ivanka Trump, had a vision of a historic Rose Garden ceremony to sign a background checks bill into law. But NRA chief Wayne LaPierre promptly threw cold water on the idea, talking Trump out of the idea when LaPierre called him to discuss it.

Trump may have placated the NRA for now. But the failure of the Trump administration and congressional Republicans to meaningfully address gun violence could constitute a fatal death blow to their 2020 electoral chances to win back suburban voters and especially suburban women, a crucial segment of the electorate where Democrats are gaining ground.

Democrats are making headway and overtaking Republicans in suburban districts

In 2018, Democratic challengers flipped 40 seats in the House of Representatives largely by winning over college-educated suburban voters, according to data compiled by CityLab, which found that 22 of the 40 flipped districts were located in dense suburban or sparse-suburban districts.

The Democratic wave is rapidly transforming places like the formally Republican stronghold of Orange County in Southern California, where Democrats pulled off the once-thinkable goal of winning back four GOP-controlled seats in 2018.

And in August of 2019, the Orange County Democratic Party announced that registered Democrats now outnumber registered Republicans in the area, a striking development in an area that has been dubbed "Reagan country" for decades.

The Cook Political Report's Dave Wasserman noted that when Democrats held the House majority in 2007, they held 233 seats that represented 32% of America's total land area. They currently hold almost the same number of seats, but they cover just 20% of the US' total landmass.

Election analyst Amy Walter, also of the Cook Political Report, wrote that "the collapse of GOP in suburbs has been remarkable," adding that for many suburban voters, "the 'good economy' isn't enough to overcome the dislike these voters have for Trump's rhetoric & behavior. And, the shootings in Dayton/El Paso only help make [the Democrats'] case that the country can't afford 4 more years of this kind of divisiveness."

Read more: Here's why the once solidly Republican state of Texas could become a ticking time bomb for Trump's GOP

Republicans too are sounding the alarm about Democrats' surge in the suburbs — especially after nine Republican House representatives all decided to call it quits and decline to run for re-election.

In July alone, four members of Texas' Republican congressional delegation announced they do not plan to run for re-election in 2020, almost a year after Democrats came within striking distance of beating Republican Sen. Ted Cruz, and after they flipped two suburban districts in Houston and Dallas in 2018.

Three of the Texas representatives, Reps. Kenny Marchant, Pete Olson, and Will Hurd, represent majority-nonwhite and suburban districts that have been trending Democratic over the past several years, giving Democrats renewed hope of flipping those seats and putting Republicans on notice.

Matt Mackowiak, the chairman of the Travis County GOP which covers the city of Austin, begged his fellow Republicans to not to retire, tweeting on August 3, "I don't know who needs to hear this. But enough goddamn GOP congressional retirements. Every retirement threatens GOP's chance to take back the majority," imploring members of Congress to "suck it up. Win your re-elect. Fight socialism. Don't quit."

Rep. Will Hurd was one of four Texas Republicans to retire in 2019, putting his district in reach for Democrats. Reuters/Erin Scott

Gun restrictions are popular among the suburban voters who are rapidly fleeing the GOP

There's a mounting amount of evidence that gun control will be a top priority for voters in GOP-represented suburban districts in areas of Arizona and Texas, which Democrats hope to flip blue.

Even close to 90% of Republicans and Trump voters routinely support universal background checks in public opinion surveys.

And as Bloomberg's Sahil Kapur recently reported, exit polling from the 2018 midterms shows that gun reform was among the top five electoral priorities for all voters, and those who supported gun control measures backed Democrats 76% to 22%.

And even more recent national polling from Politico and Morning Consult conducted from August 5-7 after the El Paso and Dayton shootings shows majority support for stricter gun laws among suburban voters and especially among GOP women — a huge warning sign for Republicans:

75% of suburban voters supported stricter gun laws, as do 55% of those who voted for a Republican in 2018 and 59% of Republican women.

91% of suburban voters and 93% of Republican women supported background checks on all gun sales.

71% of suburban voters and 64% of Republican women supported banning assault-style weapons.

75% of suburban voters and 69% of Republican women supported banning high-capacity magazines.

83% of suburban voters and 81% of Republican women supported a mandatory three-day waiting period for purchasing a gun.

And 82% of suburbanites and 84% of GOP women supported raising the minimum age to buy a gun to 21.

Read more: The fight over guns isn't between gun owners and non-gun owners, it's between people who own lots of guns and everyone else

Another new survey conducted by the Republican Main Street Partnership and Public Opinion Strategies found similarly high levels of support for background checks and other gun restrictions specifically in polling female voters in five suburban congressional districts, four of which flipped from Republican to Democratic control last year. The fifth, North Carolina' ninth district, will hold a special election for Congress later this fall.

Importantly, Republicans are already at a disadvantage among female voters in those districts. The RMPS/Public Opinion Strategies poll found that not only is Trump's approval rating underwater among those voters, but 51% already lean towards the generic Democratic candidate in their district compared to 33% who lean towards the generic Republican.

84% of respondents supported a national red flag law, 88% backed a mandatory 48-hour waiting period, 76% supported banning semi-automatic assault weapons including the AK-47 and AR-15, and 72% backed banning high-capacity magazines.

The survey further confirmed that stopping gun violence will be one of the main issues driving suburban women in swing districts.

It found that 30% of all women and 38% of independent women said working to prevent gun violence was their top priority in the next election, and 60% of respondents said they would be "more likely" to support a Republican congressional candidate who supported the aforementioned gun proposals.

Impactful gun control legislation is unlikely to pass through a GOP Senate

While the issue of gun violence might help Democrats gain even more seats in the House of Representatives, any gun control legislation has close to a zero percent chance of passing as long as the GOP holds the Senate, which they currently control by a margin of 53 to 47 seats after expanding their lead in 2018.

In February, the House of Representatives passed two bills which aim to strengthen background checks — one which would close the so-called "gun show loophole" by requiring background checks on all private gun sales, and another which would extend the required amount of time to process a background check.

While some Republican members of Congress like Sen. Lindsey Graham of South Carolina and Rep. Adam Kirzinger of Illinois spoke out in support of some gun restrictions after the two shootings, Sen. Majority Leader Mitch McConnell has not brought either of the House-approved background check bills to the floor of the Senate.

Read more: Here's the House gun control legislation Mitch McConnell refuses to take up in the Senate after the mass shootings in El Paso and Dayton

With McConnell cultivating a "legislative graveyard" in the chamber, Democrats' best chances of passing ambitious gun reform legislation are to win back both the presidency and the US Senate.

While it's too early to definitively rule anything out, flipping back control of the Senate would be a heavy lift for Democrats.

It would most likely require Democratic Sen. Doug Jones being re-elected in Alabama, and also winning the seats currently held by Republicans in Colorado, Arizona, and Maine as well as an additional seat in either North Carolina, Iowa or Texas.

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