The thing is, this case should never have come up.
If the US Justice Department had followed correct procedure and asked the US government to ask the Irish government for access to the data, as per the existing agreements, then all would have been well.
Instead, they chose to take the high-handed shortcut of demanding the data direct from Microsoft, who quite rightly (and perfectly legally) refused.
So now they're trying to use bully-boy tactics to force Microsoft to do something against the law.
This is the "Justice" Department, how ironic.