A future Enron
The argument here is complete bollocks. If data were held in, say, Ireland the USA would need to request an Irish court to release the data. If the Irish court was satisfied that there is good reason then it would probably order a release of the necessary documents, much as it would agree an extradition of a person.
Requesting a court in the USA for access to data held in the USA is also what the FBI should do, but it is just much simpler for them to go & grab it.
What this will stop is fishing expeditions and the use of data for purposes other than nailing criminals. There has long been a suspicion about the USA helping themselves to trade secrets.