&gt; <i>it seems to me that an American court has the power to demand that an American citizen produce an item or information under his control, even if it happens to be in another country</i><p>Does the American government have the power to compel someone to violate foreign law in order to produce an item held in a foreign country?  Can the American government force an American citizen to violate Greek law and take a million Euros out of Greece for that hypothetical divorce settlement?<p>This is the scenario in question here.  It is illegal in Ireland for Microsoft to provide the requested information to the US Government.  The data resides in Ireland so complying would require performing an illegal act in Ireland.  Does US law for some reason override Irish law?  Can the US government compel Microsoft to violate Irish law?