Should US authorities have the right to access emails stored anywhere in the world if the email service provider is headquartered in US? Microsoft thinks not.
At the second circuit court of appeals on Wednesday, the latest chapter in its long running standoff with the Department of Justice over a US warrant demanding access to email stored in Microsoft's datacentre in Ireland unfolded.
Microsoft has previously contended in court -- and lost on two occasions -- that the DoJ shouldn't rely on a US warrant to force Microsoft to hand over email stored in Ireland. Rather, it should rely on the mutual legal assistance treaty (MLAT) it has in place with Ireland.
Microsoft's counsel Joshua Rosenkranz on Wednesday told the court that the DoJ had exceeded its authority, the Guardian newspaper reported.
"This is an execution of law enforcement seizure on their land... We would go crazy if China did this to us," said Rosenkranz.
Another point of contention is whether the emails are private records or Microsoft's business records. If users' email are the latter, the DoJ believes Microsoft should be required to produce them under a search warrant no matter where the emails are located.
"This notion of the government's that private emails are Microsoft's business records is very scary," the paper quoted Rosenkranz as saying.
The case is viewed as a landmark battle that will have implications for privacy, sovereignty, and legal jurisdiction in a world where cloud computing is the norm.
Microsoft has gained support from over 100 individuals and organisations including Apple, Cisco, Verizon, the EFF, eBay, HP, and even Ireland itself, which said individuals and organisations should be able to have confidence in rules and processes in place to safeguard privacy.
Microsoft reiterated what is at stake for US companies and citizens if the DoJ wins the case.
"If the government prevails here, the United States will have no ground to complain when foreign agents -- be they friend or foe -- raid Microsoft offices in their jurisdictions and order them to download US citizens' private emails from computers located in this country," Microsoft said in its appeal brief.
Despite widespread support for Microsoft's position, a victory for the company would bring its own complications for the question of jurisdiction, according to Jennifer Daskal, a lawyer at the Washington College of Law.
As she points out, it would mean that the location of the data rather than a company's headquarters would determine jurisdiction, which is complicated in multi-region cloud computing architectures.
"Data is highly mobile, divisible, and generally subject to third-party control. Data's mobility makes data location a highly unstable and potentially fleeting basis of jurisdiction. Its divisibility means that relevant data (particularly when one starts considering large databases) may not even be housed in a single location, but partitioned and spread across multiple jurisdictions.... As a result, data location turns out to be an often arbitrary and unstable determinant of jurisdiction," she said.