Microsoft and the US government have clashed in an appellate court hearing on law enforcement access to emails stored overseas.

Allowing the government to carry out its warrant for its emails stored in Ireland could create “a rule for global chaos”, a lawyer for Microsoft, Joshua Rosenkranz, said on Wednesday in the New York federal appeals court.

Siding with the government in the case could give free rein to foreign governments to demand comparable records from US interests, Rosenkranz said.

• Apple has launched a new iPhone range
• Netflix growth in Australia slows for first time
• The smartphone rip-off is over—except for iPhone

“If we can do this to them, then they can do that to us,” Rosenkranz said.

“We would go crazy if China did this to us. Why? Because this case is about sovereignty.”
US officials in December 2013 persuaded a magistrate judge to grant a warrant to access to a Microsoft-based email account that was suspected of being used in narcotics trade.

But Microsoft refused to comply, saying the records were stored at a data centre in Dublin, Ireland. A US district court sided with the government.

The government has argued that the specific location of the records is irrelevant because Microsoft, as a US company, is subject to US rules.

“Under international law … the norm is that sovereigns have jurisdiction over entities before them and can compel them to produce materials,” said Justin Anderson, an assistant US attorney.

Members of the three-judge panel seemed open to both sides and extended an oral argument originally scheduled for 24 minutes well past an hour.

“The implications of what we do here are obviously broad,” said appellate judge Gerard Lynch.
Microsoft has won backing from numerous tech, media and telecom heavyweights, including Apple, the Washington Post and Verizon.

The Center for Democracy and Technology, which has supported Microsoft, warned of an international “wild west” if the warrant is upheld as foreign governments seek to seize data held in the US.