I like to think that there's been a regular effort to stay ahead of those who might try things, and often they get thwarted early on and we just don't hear about it. Because if that's not what's been happening for years, and things that do happen are only because of mistakes or blatant removal of the efforts (looking at you, Cheney)...then no one except the few historically acts has bothered to try anything, and that seems really unlikely given how much the rest of the world "loves" us so much.
Hardly a fan of Trump, but he is a former President and due the protection that apparently was not fully engaged. Why it wasn't in place needs to be discovered and fixed. For all sides, this isn't partisan, this is basic security. And if this is broke, what else is?