If the people really want to overthrow the government, some jacked up defenses around capitol buildings won't stop anything imho, it just means the resistance will bring heavier weapons to match.
A few years(?) ago, Mitch McConnell's dinner at a restaurant was interrupted by protestors yelling at him. And that was after what happened to Gabby Giffords.
Targets with higher ROI are available to people willing to take, ahem, kinetic actions.