You also need Tribunes whose veto only lasts for as long as they are physically present in the premises.
This would single-handedly eliminate Trump's power. Dude is literally never working. Three hours on a good day.
That said, we do pretty much have a system similar to that with the filibuster (the real one, not the shitty administrative one). Stand and deliver!
If people start shooting up polling centers on election day then I'm leaving the country and you can enjoy your civil war.
At least in my state, polling centers have police at every location (actually, it's that's literally built into the system: we can't open the place up unless the police deliver the keys and other stuff to us, so every location has a police officer or two). And unlike the election workers, police get to work in shifts, so they aren't completely exhausted.
It's already necessary to enforce those "100 feet, no politicking" laws (and believe you me, people stand at the 100 feet mark on the dot), and you never know when someone will walk in and start harassing voters or election workers, so even a single policeman (it was a woman last time, for what it's worth) is a worthy investment. Unlike at, say, a public place of worship which meets every week.
Which is surely not going unnoticed. Next foreign adventure we get ourselves into, we're likely going to have a hell of a time finding locals willing to risk life and limb on our behalf.
You know, this is what people meant in Latinthread about there being smarter and dumber ways of going about war.