The United States government was founded on the principle of separation of church and state. That being said, if the U.S. could select a single holy site and have everyone in America agree that it was not to be trifled with, the frontrunner would be the Tomb of the Unknown Soldier — the monument to those who fought and died for the U.S. but remain unidentified.
Arlington National Cemetery's Tomb of the Unknowns is guarded 24 hours a day, seven days a week by the tomb sentinels of the 3rd Infantry Regiment, The Old Guard. And these guys do not mess around. When it comes to discipline, The Old Guard have such firm bearing that they can get stabbed in the foot with a bayonet and keep standing guard.
They will guard the tomb during hurricanes. They will stay at their post during epic snowstorms. There is nothing they won't do to maintain a watchful eye on what might be America's holiest of holies.
So, it should come as no surprise that when tourists are around the tomb, these sentinels don't tolerate anything short of solemnity and adherence to the rules that govern such hallowed ground. In the past, numerous videos have shown how the Old Guard responds to those who try to get a closer look at the tomb by crossing barrier obviously in place to keep onlookers away.
And that's just what they do when you try to cross the barrier for a photo (to fast-forward, the sentinel admonishes a woman for crossing the line at 1:00 into the video). Imagine what happens if someone suddenly tries to reach out and touch the Tomb of the Unknown Soldier itself.
Aside from getting manhandled (and probably tazed) by the Arlington Police, the Tomb Sentinels are carrying fully functional weapons. Whether they're loaded weapons or if the sentinels have ammunition remains unknown (many sources say they don't), but that's not a reason to go testing the theory. What is known, however, is the sentinels will move much faster than we're used to seeing them in order to stop you.
Quora user Chris Leonard, who used to be a part of the Old Guard, reminds us that maintenance work is done on the aging tomb all the time, but workers are expected to show the same reverence in touching the tomb for repairs that the sentinels themselves would observe — and the sentinels are watching them every second they're at work.
Leonard recalled a moment where a maintainer touched the tomb in a manner inconsistent with the respect called for by the monument — he was leaning on it. The sentinel yelled at the man to stop as he quickly approached. The sentinel then "cross checked" the maintenance worker.
The maintenance worker later apologized to the sentinels.