Mass shootings have shit all to do with who is President. In fact there seems to be a run on guns and ammo when a Democrat is elected because all the gun nuts work themselves up about how "the guvmint coming for muh guns!"
We have an estimated 400,000,000 guns in this country, and like all humans are barely above animal status when it comes to emotions and motivations. Add in social media. If we DIDN'T have mass shootings that would be the surprise. I've ridden in cars with a couple people that built up so much road rage that I was very glad they didn't have a gun with them. We are nothing but chimps that are allowed to carry baseball bats with nails in them. Whatever, as someone who votes Democrat (until such time as the GOP becomes more sane, which I figure is "never"), any Democrat who want to make a change in anything should leave guns alone. We are hopelessly, pathetically addicted to our toy guns and that will not change. Hell I know lefties who wouldn't vote Democrat if they thought they'd lose their gun collection. We'll just continue to be the grand experiment for the rest of the world to watch and learn from.
I do feel the 2nd amendment is obsolete. It's intention was to protect plantation owners in a day of front-loading muskets. But it's there and boys gotta have their toys, it won't change.