A federal court has held Syria’s government liable for the targeting and killing of an American journalist as she reported on the shelling of a rebellious area of Homs in 2012. The decision could help ease the way for war-crimes prosecutions arising from the Syria conflict.

Issued by the United States District Court in Washington, the decision awarded $302.5 million to relatives of the journalist, Marie Colvin. Of that sum, $300 million is punitive damages for what Judge Amy Berman Jackson, in her ruling, called “Syria’s longstanding policy of violence” that aimed “to intimidate journalists” and “suppress dissent.”

“Our hope is that this case in some ways will provide a blueprint for future cases against the regime” led by President Bashar al-Assad, said Scott Gilmore, a lawyer for the Colvins, after Judge Jackson’s ruling was issued on Tuesday.

Collecting the money will be an arduous effort that, at best, will take years, Mr. Gilmore said. But more significant, he said, the ruling was the first time a court had held the Syrian government responsible for an atrocity from a war convulsing the country for nearly eight years.