[been_lurking]

oes that mere risk give us authority to attack and destroy ships of other soveriegn nations that are not themselves violating international OR U.S. Law?

You are the only one suggesting "Attack" and "destroy", so your argument is a complete strawman.

None the less, boarding, inspecting, and seizing of nuclear arms shipped to Iran is in keeping with current international treaties and U.N. sanctions. Therefore, yes the U.S. would be acting legally.

[CharlesWayneCT]

The original question, from the post here, was:

Dr. Paul, if a shipment of nuclear tipped missiles was heading from North Korea to Iran, knowing the position of Ahmadinejad and the mullahs, would you stop that ship or sink it?

So maybe people are only talking about stopping and boarding, but the actual question included sinking, which would be "attack and destroy".