The woman, named as 42-year-old Anna Sacoolas, initially cooperated with police, but left the country after the U.S. Embassy in London asserted her diplomatic immunity.
The incident has caused tension between Britain and the United States at the highest levels of government, with British Prime Minister Boris Johnson asking President Trump to waive Sacoolas’s immunity so she could return to Britain to cooperate with the investigation into Dunn’s death.
But on Wednesday Trump told reporters that even though there had been a “terrible accident,” Sacoolas still retained her diplomatic immunity.
What is the history of diplomatic immunity?
Legal immunity for diplomats and envoys has a long history — historians can find similar ideas in Sanskrit accounts of ancient India. The modern standards for diplomatic immunity were first set during a meeting of ambassadors of European states in Vienna in 1814 to 1815. This was later codified by the Vienna Convention on Diplomatic Relations in 1961, an international treaty that has been signed by 192 countries around the world.
The only U.N. members that have not signed are Palau, the Solomon Islands, and South Sudan.
What does the Vienna Convention say about diplomatic immunity?
The convention says specifically that a “diplomatic agent shall enjoy immunity from the criminal jurisdiction of the receiving State” and that the diplomat “shall not be liable to any form of arrest or detention.”
The convention adds that this does not mean that the diplomat is exempt from his or her own nation’s laws and adds that their own government can choose to waive their immunity in certain circumstances. The diplomats’ families members are also given immunity as long as they are not nationals of the host country, as well as members of staff.
If they do not, the host country has limited recourse, other than making the diplomat persona-non-grata to expel them. In cases of “last resort,” it can detain a diplomat if they are deemed a danger to themselves or others.
How often is diplomatic immunity invoked?
There are large numbers of people around the world who hold diplomatic immunity. According to statements made by Britain’s then-foreign minister Jeremy Hunt, there were around 23,000 people in Britain alone who held the status in 2017.
The net effect can be large. A British transport group said earlier this year that foreign diplomats owed more than £116 million ($144 million) in unpaid London congestion charges.
Claiming diplomatic immunity is more unusual in more serious cases. In 2017, there were 12 serious offenses committed by people eligible for diplomatic protection in Britain, Hunt said, including one case of possession of a firearm and one case of sexual assault
How can immunity be waived and how often does it happen?
Immunity can only be waived by the diplomat’s country; the diplomat cannot choose to waive it of their own accord. In practice, the decision to waive or not waive immunity often depends on the specifics of the case.
The United States has applied diplomatic immunity in cases where U.S. citizens have killed people in incidents overseas, including two controversial cases in Pakistan, one in 2011 and one in 2018.
However, the United States has also compelled foreign nations to make their citizens give up diplomatic immunity. One well-known case occurred in 1997, when a Georgian diplomat drove into a number of cars near Dupont Circle in Washington, leaving a 16-year-old girl dead.
The diplomat, who was believed to have been drinking heavily and speeding, was sentenced for involuntary manslaughter and aggravated assault after his immunity was waived. He served three years of his sentence.
What does the law say in this case?
Some legal experts have questioned whether full diplomatic immunity should apply to Sacoolas and Johnson, the prime minister, has said it was not an appropriate use of immunity.
“I do not think that it can be right to use the process of diplomatic immunity for this type of purpose,” Johnson said on Monday.
But the United States has so far pushed back, with the U.S. Embassy arguing that immunity is “rarely waived.”
Trump was photographed holding a series of talking points on Wednesday that appeared to rule out Sacoolas returning to Britain.
“(If Raised) Note, as Secretary Pompeo told Foreign Secretary [Dominic] Raab, that the spouse of the U.S. Government employee will not return to the United Kingdom,” the note, marked “secret,” read.