Osama bin Laden's son-in-law was sentenced in life in prison Tuesday for conspiring to kill Americans.

Sulaiman Abu Ghaith, a spokesman for al Qaeda from before 9/11, was convicted in March, in what the Justice Department and some Democrats hailed as a victory for the administration's approach to trying terrorism suspects in civilian courts. 

ADVERTISEMENT

Attorney General Eric HolderEric Himpton HolderIf Roger Stone were a narco, he'd be in the clear Trump flexes pardon power with high-profile clemencies They forgot that under Trump, there are two sets of rules MORE applauded the life sentence on Tuesday, saying the case was evidence that federal courts could provide "swift and certain justice" for terrorism suspects. 

"We will continue to rely on this robust and proven system to hold accountable anyone who would harm our nation and its people," he said. 

In March, Abu Ghaith was convicted on charges of conspiracy to kill Americans and providing support to al Qaeda. He was also convicted of providing support to the terrorist group.

Some Republicans last year had called for Abu Ghaith to be tried in a military court at the Guantánamo Bay prison in Cuba. 

Senate Intelligence Committee Chairwoman Dianne FeinsteinDianne Emiel FeinsteinDemocratic senators ask DOJ watchdog to expand Giuliani probe House passes bipartisan bill to create women's history museum Democrats bullish on bill to create women's history museum: 'It's an election year' MORE (D-Calif.) noted the Justice Department had secured more than 500 terrorism convictions since 9/11. 

The sentence "once again shows our federal criminal court system works and that we can successfully bring al Qaeda terrorists to justice," she said. 

Abu Ghaith was the highest-ranking al Qaeda leader to face trial in a civilian court. Judge Lewis Kaplan handed down the sentence Tuesday in a federal court in Manhattan. 

"You, sir, in my assessment, are committed to doing everything you can to assist al Qaeda in its mission to kill Americans," Kaplan said, according to Retuers

The judge dismissed defense lawyers’ pleas for a reduced sentence. Abu Ghaith’s attorneys argued that their client was guilty of only spreading propaganda and had not participated in planning al Qaeda’s attacks.