In the aftermath of recent school shootings, a familiar pattern has played out in the debate over guns.Gun-control advocates push for tougher laws, including universal background checks to prohibiting the sale and possession of AR-style long guns. The National Rifle Association and many Republican leaders insist the root of the problem is not guns but a range of issues such as mental health, school security, video games and excessive prescriptions of attention-deficit disorder drugs such as Ritalin.Gun-control advocates call the strategy a clever smoke screen to avoid having to talk about gun control. The cycle repeats with the next mass shooting.The talking points have evolved over the years and become part of the NRA playbook in response to recent school shootings — and in turn have been echoed by Republican leaders in states such as Texas that have experienced gun violence in schools.Here is a closer look at contentions by the NRA:SCHOOL BUILDINGS: After the 2012 massacre at Sandy Hook Elementary School that killed 26 people, the NRA launched its School Shield program that offers to review and assess school properties and identify ways to make them harder to penetrate by a would-be school shooter. Among the thoughts are fewer entrances and exits, ensuring the administration offices are within sight of the main entrance to quickly see who is entering, fewer shrubs and trees up against the building, bulletproof windows and doors, and the ability to lock a classroom from inside the room.School security experts say those structural changes are important to making school safer — but they don't replace other steps such as finding ways to identify students who are in some emotional trouble and encouraging students to report concerns about a classmate."Any type of hardware or equipment is only as strong as the weakest human link behind it," said Kenneth Trump, president of the National School Safety and Security Services, a Cleveland-based consulting firm.ARMING EDUCATORS: President Donald Trump, the NRA and, most recently Texas Lt Gov Dan Patrick, all have said that having armed and trained educators would allow a school gunman to be confronted sooner and prevent mass casualties. The president has also suggested paying bonuses to teachers willing to undergo training and carry a firearm on campus.There are some schools around the country that already allow educators to bring a firearm into the school. Consulting firms have sprouted up that provide specialised training for teachers.Some law enforcement experts caution that arming teachers isn't practical and can create its own host of problems — from bad decisions about when to shoot to leading to PTSD for educators who find themselves in the situation. Law enforcement officials also say it could lead to confusion for officers responding to a shooting and not knowing who the bad guy is."What an individual officer or a team of officers will do in an active shooter incident calls on every aspect of their overall training and policing. And that's one of the reasons why you'd be hard-pressed to find someone in policing who thinks it's a good idea to arm teachers," said Rick Myers, executive director of the Major Cities Chiefs Association."Teachers' training and expertise has nothing to do with police tactics — shoot-don't-shoot decision making, the psychological trauma that accompanies violence, all the things that are built into what police officers deal with on a daily basis."RITALIN: The NRA's incoming president, retired Lt Col Oliver North, recently blamed school shootings on the drug Ritalin, which is used to treat attention deficit hyperactivity disorder. His comments came in the days after the Santa Fe, Texas, school shooting. However it's not known if the suspect in that case had been prescribed that drug or was using it.George DuPaul, a psychologist at Lehigh University in Pennsylvania whose research has focused on ADHD treatment, has said research doesn't support North's claim."There's really no evidence whatsoever that links treatment for ADHD with Ritalin and drugs like that with violence, let alone gun violence," he said.VIDEO GAMES: North and others also have blamed a "culture of violence" and specifically video games that they say breed violence and encourage school shooters.There has been research for decades on this topic but few definitive conclusions. Some studies suggest that playing video games leads to anti-social behavior and aggression, while others suggest it can have a calming effect and that there's no correlation to increased violence among those who play the games.Ironically, North played a role in marketing and voicing one of the more popular video games: "Call of Duty: Black Ops 2," which features the retired Marine in one of its story lines.One such study, created by a task force of the American Psychological Association, reported in 2015 that "the research demonstrates a consistent relation between violent video game use and increases in aggressive behavior, aggressive cognitions and aggressive affect, and decreases in prosocial behavior, empathy and sensitivity to aggression." It cautioned there was no single reason for violent behavior but violent video games was one such factor.Earlier this year, a study by the University of York found no correlation between gaming and leading players to become violent: "''The findings suggest that there is no link between these kinds of realism in games and the kind of effects that video games are commonly thought to have on their players."In 2011, the US Supreme Court ruled that video games were protected by the First Amendment and barred California from banning the sale of violent video games to children. In the majority decision, then Justice Antonin Scalia wrote: "Psychological studies purporting to show a connection between exposure to violent video games and harmful effects on children do not prove that such exposure causes minors to act aggressively. Any demonstrated effects are both small and indistinguishable from effects produced by other media."MENTAL HEALTH: The NRA has sent mixed messages on how it believes the US should address mental health and the possession of firearms.It applauded President Trump's move early in his term to overturn an Obama administration rule that required the Social Security Administration to provide information to the gun-buying background check system on recipients with severe mental disorders. Then-President Barack Obama saw it as a common-sense solution to flag problematic behavior of people buying guns, but the gun lobby viewed it as arbitrarily stripping away a person's Second Amendment rights.Earlier this year, the NRA expressed some support for so-called "red flag" laws but has not advocated for those measures, which allow relatives, guardians or police to ask judges to temporarily strip gun rights from people who show warning signs of violence. However, it also has expressed concern about the right to possess firearms being stripped away "without due process."