Could The US Military Defeat One Imperial Star Destroyer?

On the terms most people imagine the fight, yes. If an Imperial Star Destroyer were foolish enough to descend into Earth's atmosphere, the US military would likely make short work of it, because nuclear missiles are powerful enough to break its shields and blow it apart. The problem is that the Empire would never fight that way. It would stay in orbit, outside the reach of anything that can be launched at it, and run a Base Delta Zero.

What a single Star Destroyer actually is#

Start with scale, because the mental picture people carry tends to be off in both directions.

The Imperial-class Star Destroyer is 1,129 metres long. About a kilometre of dagger-shaped warship. Despite that size it was deployed as a patrol ship and an escort, not as a rare flagship. The Empire had a great many of them.

Worth keeping in perspective how far up the ladder that is not. The Executor-class Star Dreadnought ran 19,000 metres and carried over 5,000 turbolasers and ion cannons. A single Imperial-class is one of the routine units the Galactic Empire parked over a world to keep it in line.

The thing that made it a threat to planets was never a superweapon. It was position.

The atmospheric fight is the one Earth wins#

The video's opening scenario is deliberate, and it is right. Bring the Star Destroyer down inside the atmosphere and you have handed away everything that makes it dangerous.

A ship in atmosphere is inside the operational envelope of ground-launched weapons. It is a kilometre-long target that cannot dodge, at an altitude where warheads can reach it. Nuclear missiles are enough to bring down its shields and destroy it.

There is precedent for large capital ships being killed by comparatively small attacks. At the Fondor Shipyards, an eighteen-year-old Anakin Skywalker destroyed a ship by planting a proton grenade on its hypermatter reactor and taking out a missile silo with a borrowed launcher. Big warships have soft internals and known weak points.

The catch is that this is a scenario the Empire would have to volunteer for.

Base Delta Zero is the fight Earth loses#

The Imperial answer to a hostile surface is not to land on it. It is Base Delta Zero: sustained orbital bombardment, continued until the target is stripped.

Star Destroyers were capable of rendering entire planets lifeless this way, though not completely annihilating them. Unlike an actual superweapon, it usually required sustained bombardment, a combined assault from a fleet of ships, sabotage of planetary shields, or some combination of the three.

It got used. Imperial Admiral Uther Kermen launched a Base Delta Zero on Milagro to deny its manufacturing facilities to the New Republic, ending a three-month campaign. Earlier, in the early years of the Empire, planetary shields over Caamas were sabotaged so the peaceful Caamasi people could be exterminated in a Base Delta Zero bombardment, an atrocity that caused a political firestorm decades later when the details came out.

General Grievous did something comparable to Humbarine during the Clone Wars, an hour-long orbital bombardment of a heavily populated, urbanised founding world of the Republic.

Against that, Earth has no answer. The US does not have nuclear missiles that reach far enough into space to threaten a ship in orbit, and the Star Destroyer never has to come lower. It would soon annihilate Earth's defences from a position nothing could reach.

The one thing that changes the equation#

There is a defence that works in Star Wars, and Earth does not have it: planetary shields.

At Hoth, Admiral Ozzel's mistake gave the Rebels warning, and they activated the deflector shield protecting Echo Base in time. That single move made orbital bombardment impossible. The Empire had to disembark troops beyond the shield's range and send AT-ATs overland to destroy the generator, which is the only reason there was a ground battle at all.

That is the whole shape of planetary warfare in the setting. If you can raise a shield, the fleet in orbit is neutralised and has to come to you. If you cannot, the fleet never needs to come to you at all.

Earth cannot raise a shield. So the Empire keeps the range advantage indefinitely.

The honest verdict#

The question splits cleanly in two.

Can the US military destroy an Imperial Star Destroyer? Yes, if the ship enters the atmosphere and stays there long enough to be hit. That is a real vulnerability and Star Wars capital ships have died to less.

Can the US military defeat an Imperial Star Destroyer? Not on the Empire's terms. Winning requires the enemy to fight badly. Any competent Imperial captain sits in orbit, waits, and burns the surface at leisure while nothing fired from below gets anywhere near.

The only Star Destroyers that lose to a planet are the ones commanded by someone who decides to come down and have a look.