We've been reporting over and again about how the FBI was citing a 1789 law, the All Writs Act, to compel Apple to assist the authorities in unlocking the iPhone used by extremist Syed Farook, who along with his wife killed 14 people in San Bernardino County in December.

In a sense, the law allows for judges to issue orders for people or companies to do something despite Congress not passing laws to cover specific instances. The All Writs Act is the law that led a federal magistrate ordering Apple to write code and unlock Farook's phone, an order that was no longer necessary because the authorities said Monday they cracked the phone without Apple's assistance. The government also said it wouldn't hesitate to use the "court system" to require other tech companies to weaken their security, too.

According to the American Civil Liberties Union, the US government has cited the All Writs Act in 63 cases since 2008 to compel Apple or Google to assist in accessing data stored on an iPhone or Android device. Most of the orders involved Apple. "To the extent we know about the underlying facts, these cases predominantly arise out of investigations into drug crimes," said Eliza Sweren-Becker, an ACLU attorney.

Here are the cases.

How much assistance was required by Apple and Google is not clear. We know that, insofar as the San Bernardino shooter's phone was concerned, Apple's required assistance was unprecedented. In a statement to Ars, Google said it was never ordered to perform a service of that magnitude. "We carefully scrutinize subpoenas and court orders to make sure they meet both the letter and spirit of the law. However, we've never received an All Writs Act order like the one Apple recently fought that demands we build new tools that actively compromise our products' security," Google said in a statement.

Apple and privacy groups have argued that the government was abusing the All Writs Act, while the government has asserted that it has been employing the All Writs Act as it was intended. There is only one known case in which a judge balked at the assertion that the All Writs Act requires a tech company to unlock a smartphone. That case involved a drug investigation.