Relatives of the victims filed a lawsuit against senior officials at the US Defense Department and the Central Intelligence Agency in 2012, arguing that the killings were illegal and violated constitutional rights of the US citizens.
Judge Rosemary Collyer of the US District Court in Washington threw out the case on Friday, saying that US officials cannot be held personally responsible for the killings.
"The question presented is whether federal officials can be held personally liable for their roles in drone strikes abroad that target and kill US citizens," Collyer said in her opinion. "The question raises fundamental issues regarding constitutional principles, and it is not easy to answer."
The lawsuit was brought against former defense secretary Leon Panetta, former CIA director David Petraeus and two senior military commanders.
According to the lawsuit filed on July 18, 2012, the killings of US-born Muslim cleric Anwar al-Awlaki, his 16-year-old son Abdulrahman al-Awlaki and naturalized US citizen Samir Khan were unconstitutional.
A CIA drone strike killed al-Awlaki and Khan in Yemen in September 2011. In October 2011, another drone attack in Yemen left al-Awlaki's son and six other people dead.
In their lawsuit, relatives accused Panetta, Petraeus, and the two military commanders of approving and directing the strikes.
They said that the three assassinations committed by the CIA violated US legal guarantees, including the right to due process.
“There is something terribly wrong when a 16-year-old American boy can be killed by his own government without any accountability or explanation," said Pardiss Kebriaei, a lawyer at the Center for Constitutional Rights, which is representing the relatives, along with the American Civil Liberties Union.
Washington has stepped up its assassination drone operations in Yemen, as part of its official targeted-killing program, over the past few years.
US officials claim that the attacks target militants, but local sources say civilians have been the main victims of the airstrikes, which have also been launched against other Muslim countries, such as Afghanistan, Pakistan, and Somalia.
The US has come under fire for increasing its killer-drone attacks in Yemen, where the people have held many protest rallies to condemn the violation of their national sovereignty.
RA/MB