In the aftermath of two deadly mass shootings in Texas and Ohio, U.S. political leaders made a series of statements on gun violence that were unsubstantiated, lacked context or were seemingly contradictory.

Here we look at some of those statements and present the facts.

As of this writing, 22 people were killed and 26 were injured on Aug. 3 in a shooting at a Wal-Mart in El Paso, Texas. Police reportedly believe the alleged shooter, Patrick Crusius, 21, who is being held in custody, posted an anti-immigrant manifesto shortly before the shooting. “This attack is a response to the Hispanic invasion of Texas,” the document reads.

Hours later, in the early morning hours of Aug. 4, nine people were killed and 27 were injured in the streets of Dayton, Ohio. The alleged shooter, Connor Betts, 24, was killed at the scene by police. Law enforcement officials have yet to establish a motive for the shooting, which claimed the life of Megan Betts, the shooter’s 22-year-old sister.

Mass Shootings/ Mass Killings

The statements: “Well, first of all, our condolences to the victims and families in Dayton. Miles separate us, but our grief unites us. So be strong Dayton. You know, it’s a tragic thing. Something like this is just shocking. It is the 250th mass shooting. El Paso is 249. It is unfathomable these things continue to happen all over the country.” — Democratic state Rep. César Blanco of Texas, “CNN Newsroom,” Aug. 4

“When you look at the 250-plus mass shootings in this country this year, about 17 to 20 of them led to the loss of four lives or more. About half of those were suicides and/or domestic situations.” — Republican Sen. Tim Scott of South Carolina, CBS’ “Face the Nation,” Aug. 4.

The facts: Both men are referring to a list of mass shootings so far this year, as compiled by Gun Violence Archive. The nonprofit defines mass shooting as any single incident that involved four or more people shot or killed, excluding the shooter.

As of Aug. 3, the day of the shooting in Texas, there had been 250 mass shootings, according to the Gun Violence Archive.

Using the nonprofit’s list, we found that there have been 31 “mass killings,” which federal law defines as “3 or more killings in a single incident.” (The law does not specify if the number of those killed in a “mass killing” should include the shooter, so incidents in which the shooters were among the dead are included in our count.)

Effectiveness of Gun Laws

The statements: “The House of Representatives has passed a [universal] background check [bill]. We can fly back into Washington on Monday morning. We could pass the background check bill and people could fly back and be home for dinner. And the president needs to sign this bill. We know what to do. We know that background checks worked. We know that a ban on assault weapons worked.” — Democratic Sen. Sherrod Brown of Ohio, CBS’ “Face the Nation,” Aug. 4.

“I have the boldest plan. But my plan is actually based upon evidence. If you need a license to drive a car in this country, you should have a license to buy a gun and possess it. And we know that states that have done that have dropped — have dramatically dropped the levels of violence.” — Sen. Cory Booker of New Jersey, also a Democratic presidential candidate, NBC’s “Meet the Press,” Aug. 4.

The facts: Federal law requires background checks on those who buy guns from federally licensed firearm dealers. The Democratic-controlled House has passed legislation requiring universal background checks — which would cover private sales by unlicensed individuals, including some sales at gun shows and over the internet. But President Trump signaled that he would veto the legislation if it ever passed, and the bill has stalled in the Republican-controlled Senate.

Some states have enacted universal background check laws and, as we wrote in May, a study published in the Journal of General Internal Medicine in March found that universal background checks are associated with about a 15 percent reduction in firearm homicide. The study, led by Boston University Community Health Sciences Professor Michael Siegel, looked at homicide and suicide rates in all 50 states over a 26-year period and analyzed the relationship between various firearm laws, including universal background checks.

“After reviewing the overall literature, I would estimate that the association is somewhere between a 10% and 15% reduction” in firearm homicides, Siegel told us back in May.

Siegel, who has extensively studied gun violence, noted that his research found an “association” between universal background checks and reduced homicide rates, “but did not definitively conclude causality.” Siegel said he’d like to see another study or two confirm this research using similar methods before concluding causality.

In 2018, the RAND Corporation released several reports as part of its Gun Policy in America initiative, including one on the “Effects of Background Checks on Violent Crime.” The review identified eight studies since 2003 that examined the relationship between background checks and violent crime, and that met its research criteria. The report concluded, “Evidence that background checks may reduce violent crime and total homicides is limited, and studies provide moderate evidence that dealer background checks [which exist now] reduce firearm homicides. Evidence of the effect of private-seller background checks on firearm homicides is inconclusive.”

Research on the federal assault weapons ban, which was in place from 1994 to 2004, has been misused in the past by proponents and opponents alike.

As we wrote in our 2013 story, “Did the 1994 Assault Weapons Ban Work?” a series of three studies of the ban concluded with a 2004 study led by Christopher S. Koper, “An Updated Assessment of the Federal Assault Weapons Ban: Impacts on Gun Markets and Gun Violence, 1994-2003.”

The final report concluded the ban’s success in reducing crimes committed with banned guns was “mixed.” Gun crimes involving assault weapons declined. However, that decline was “offset throughout at least the late 1990s by steady or rising use of other guns equipped with [large-capacity magazines].”

Ultimately, the research concluded that it was “premature to make definitive assessments of the ban’s impact on gun crime,” largely because the law’s grandfathering of millions of pre-ban assault weapons and large-capacity magazines “ensured that the effects of the law would occur only gradually” and were “still unfolding” when the ban expired in 2004.

Regarding Booker’s claim about license-to-purchase laws, two studies on the effect of a permit-to-purchase law enacted in Connecticut in 1995 did find an association with drops in gun violence and suicides. But, as we wrote when Booker made a similar claim during the first round of Democratic debates in June, the studies stopped short of claiming the decline was caused by that law.

Currently, 10 states have enacted permit-to-purchase laws that require gun purchasers to obtain a permit or license, and three states require a license to own firearms, according to the Giffords Law Center.

A study of the Connecticut law published in the American Journal of Public Health in 2015 concluded that “the law was associated with a 40% reduction in Connecticut’s firearm homicide rates during the first 10 years that the law was in place.” A second study, published in Preventive Medicine in 2015, found a 15.4% reduction in suicide rates associated with Connecticut’s law (and a rise in suicide rates in Missouri after it repealed its permit-to-purchase law).

‘Charleston Loophole’

The statement: “Congress passed a bipartisan legislation to help fix the background check, something that I know a lot about. The shooter in Charleston, South Carolina, who shot my friend from the South Carolina Senate, Dylann Roof, bought the gun because the background check system was broken. We fixed that.” — Acting White House Chief of Staff Mick Mulvaney, “Meet the Press,” Aug. 4

The facts: Dylann Roof, who was convicted and sentenced to death for murdering nine people in 2015 at a historically black church in Charleston, was able to buy the gun he used in the mass shooting because of an error in the background check system. Then-FBI Director James Comey said in a statement in 2015 that a “mistake” in the process caused a delay that allowed Roof to buy the gun after waiting the required three business days. Comey said the National Instant Criminal Background Check System examiner didn’t see a police report showing Roof had previously admitted to possessing drugs, which would’ve disqualified him from getting the gun, because the wrong arresting agency was listed.

If the NICS doesn’t deny a firearm purchase within three business days, the licensed dealer can continue with the sale, which is what happened in this case, Comey explained.

As for Mulvaney’s statement, “We fixed that,” a senior administration official pointed us to the Fix NICS Act, a bipartisan measure aimed at improving the background check system records. It was incorporated into an appropriations act in 2018 and signed into law. The Fix NICS Act required federal agencies to submit semiannual certification reports to the attorney general on their compliance with record-keeping and transmission requirements, and to come up with plans to increase coordination and automated reporting. It included financial penalties for political appointees for noncompliance. It also required the attorney general to create a domestic violence initiative to prioritize domestic violence records in the NICS and called for incentives and improved information-sharing for states. And it reauthorized a state grant program for identifying and communicating criminal justice information.

The House Democrats, meanwhile, (joined by three Republicans) passed a bill in February aimed at fixing the so-called “Charleston loophole” by requiring a 10-day waiting period, instead of three days, for background checks to be conducted before a sale can proceed. Trump threatened to veto the bill if it passed the Senate as well, but the legislation hasn’t been taken up in the Republican-controlled Senate. It’s unknown, of course, whether either measure would have changed the outcome in the Roof case.