The Democrats have come out dancing in the blood of victims of a shooting, as they always do, demanding more laws that wouldn't have dine a thing to prevent this shooting. However, there were some important things learned here:
There were many on the anti gun side who want to completely eliminate the Second Amendment and outlaw guns. Let's say that the plan comes true, the 2A is repealed, and a statute making guns illegal is passed: "Ladies and gentlemen, turn them all in. Here is a gift card for some sneakers."
There are at minimum, 400 million firearms in the US, likely held by at least 100 million people. Let's say that you get 99.9% of them, which would be a miracle, since Canada and Connecticut didn't get even 50% compliance the guns they wanted registered. That would leave 400 thousand firearms and 100 thousand gun owners.
Someone will have to go out and get those missing guns. That means door to door cops kicking in doors. Many of these gun owners would not be happy about this, and this will result in a significant number of cops getting killed. The end result is that the military will wind up going door to door, and gun owners will have to turn them in, go into hiding, or fight.
One guy just committed a shooting that police admit they had no way of stopping. He was killed, but managed to kill 58 people in the process. Imagine the bloodbath if even 10% of these rogue gun owners did the same. When the dust settles, are the American people willing to see hundreds of thousands of deaths, military searches, and all of the fallout that would entail?