@lv101 - I concede that the assault ban studies showed mixed results and more time would be needed for accurate proof either way.
According to quotes of Wiki:
In 2004 the National Institute of Justice commissioned a report on the assault weapons ban.
The report also concluded that it was "premature to make definitive assessments of the ban's impact on gun crime," since millions of assault weapons and large-capacity magazines manufactured prior to the ban had been exempted and would thus be in circulation for years following the ban's implementation. Writing before the rise of mass shootings in the 2010s, the authors stated that, "[t]he few available studies suggest that attacks with semiautomatics ... result in more shots fired, more persons hit, and more wounds inflicted per victim than do attacks with other firearms," and that reducing use of assault weapons and large-capacity magazines could thus have "nontrivial effects on gunshot victimizations."
The law also had a grandfather clause allowing for anything legal prior to the ban to be possessed and even sold!
The problem was that the ban was too watered down. It should have required the surrendering or buyback of the guns. And all guns that had a high capacity or capable of rapid fire needed to be included not just some. Also, by getting too specific in naming models and features it allowed manufacturers to simply make slight alterations to the guns and then sell parts to restore the illegal nature of the weapon. IOW the law was of limited value because as it was written there were too many loopholes.
Interestingly, GHW Bush passed legislation limiting the sale of assault weapons but bizarrely targeted only foreign made assault weapons. Ford, Carter and even Reagan all endorsed an assault weapons ban. What has changed is the NRA's influence and money, so that Republicans are often afraid to support anything resembling real gun regulation.
I would say that if Trump wanted to ensure a second term the best thing he could do is pass reasonable gun control measures. Over 70% of Americans support it.