The USA does not have to physically enforce the blockade; all it has to do is use psychological warfare

[Invisibleflash]

The USA does not have to physically enforce the blockade; all it has to do is use psychological warfare. The US military uses radio transmissions to warn the ships not to proceed or force will be used.

Here...

You can listen to the actual transmission here.

(1555) ALERT: WW3 BLOCKADE! "NO SHIPS ALLOWED" CENTCOMs 'STARVE IRAN' Plan, FAKE Negotiations - YouTube