The US had jurisdiction since MU rented about 500 (?) servers in Virginia. If all of their servers were outside the US, they couldn't have done much about it.
Meaning: If they were MegaUpload.ch, they would have needed to SOPA to take the domain down. But they still would not have been able to seize the servers and arrest the operators.
tl;dr: Relating this to SOPA is a bit of a stretch.