GUANTANAMO BAY NAVAL BASE, Cuba — The war crimes trial of a driver for Osama bin Laden could bring America closer to its goal of closing the prison at Guantanamo Bay.

The 10-day trial of Salim Hamdan, in a makeshift courtroom behind coils of razor wire, offers a road map for clarifying the legal status of nearly a third of the more than 250 men still held here.

The military jury considering the case, the first American war crimes trial since World War II, adjourned yesterday without reaching a verdict and was set to return today for a third day of deliberations.

Mr. Hamdan could face life in prison if convicted of any of the charges against him — two counts of conspiracy and eight counts of aiding terrorism.

About 80 of the roughly 265 men held at Guantanamo are slated to be prosecuted by military tribunals. Mr. Hamdan’s case, stalled by years of legal challenges that reached the Supreme Court, signals those cases can move forward now.

The American government has long said it wants to close Guantanamo but has struggled get other countries to take the remaining prisoners — those not slated for prosecution — off its hands.

For those who are prosecuted, convictions could make it easier to send detainees to mainland prisons to do their time. The chief prosecutor for the Guantanamo tribunals, Army Colonel Lawrence Morris, has even predicted the trials would be like Space Shuttle launches — so routine the public mostly ignores them.

“We are confident that we can try cases to the highest standards of justice,” Mr. Morris said while waiting for the jury, six American military officers selected by the Pentagon, to reach a verdict.

The military has not said where Mr. Hamdan, a Yemeni in his late 30s with a fourth-grade education, would serve his sentence, and has suggested he could even be held at Guantanamo indefinitely.

Mr. Hamdan was never alleged to be more than a minor figure in Al Qaeda, a chauffeur to Mr. bin Laden. He was captured at a roadblock in Afghanistan with two surface-to-air missiles in the car.

He is accused of conspiring with Al Qaeda in its plots against America, but his lawyers say he was a low-level bin Laden employee who stayed with him for the $200-a-month salary.

A Pentagon spokesman, Navy Commander Jeffrey Gordon, said the completion of the 10-day trial marks “a substantial sign of progress” in one aspect of the Bush administration’s effort to eventually close Guantanamo.

The military has already released more than 500 Guantanamo detainees to their home countries, where most were eventually set free.

Some analysts, noting Mr. Hamdan’s relatively minor status in Al Qaeda, believe his trial is mostly an opening act, a demonstration of American legal system for prosecuting suspected terrorists.