I fully expect that people in the USA are going to follow their own mistakes. If the recent attack in Texas had succeeded in causing mass casualties, it would be the government's excuse for new gun control measures.
I've been saying for years that it was only a matter of time before a Charlie Hebdo or Mumbai style attack happened on U.S. soil with legally purchased firearms. Then, the gun grabbers will be out in force trying to limit access to firearms in the name of "safety". It's happening now, but the failure of the attack will prevent the gun control effort from gathering momentum.
The American people gave up Amendments 4,5 and 6 of the Bill of Rights after 9-11. Will they allow themselves to be deprived of #2 after an attack involving firearms?
Too bad it was a traffic cops and not a private citizen who thwarted the attack in Texas. Still, it proves that a good guy with a gun can prevent or mitigate mass murder.