In a decision issued Tuesday, the United States Supreme Court ruled that immigrants living in the U.S. cannot be deported for minor drug crimes absent the presence of a large quantity of a controlled substance or direct evidence of a sale.

"We must decide whether this category includes a state criminal statute that extends to the social sharing of a small amount of marijuana," Justice Sonya Sotomayor wrote for the court's 7-2 majority in Moncrieffe v. Holder (PDF), ruling in favor of a Jamaican man who was deported over possession of 1.3 grams of marijuana.

The ruling is aimed at clarifying that, under the Immigration and Nationality Act, the "aggravated felony" classification does not apply without evidence of distribution. The ruling could also influence judges' thinking on cases in states where penalties for distributing a controlled substance are broadly applied by authorities even to offenders caught with small amounts.

In the case, Jamaican national Adrian Moncrieffe, who'd lived in the U.S. legally since age 3, was deported after accepting a plea deal on a minor marijuana offense that he believed would keep him out of prison.

He was pulled over in 2007 by police in Georgia and caught with 1.3 grams of marijuana, and charged as a drug dealer despite the lack of evidence that he sought to distribute the drug. However, Moncrieffe's attorney did not inform him that a guilty plea would endanger his immigration status, because the law considers any "aggravated felony" to be a trigger for deportation. When he signed the plea, federal authorities immediately moved to deport him.

"This is the third time in seven years that we have considered whether the Government has properly characterized a low-level drug offense as 'illicit trafficking in a controlled substance,' and thus an 'aggravated felony,'" Sotomayor added. "Once again we hold that the Government’s approach defies 'the 'commonsense conception'' of these terms."