Alistair Irvine, 25, was due to appear at Santa Ana Superior Court in California, to face charges of stalking and threatening to shoot teenager Karel Taska in June.
Prosecution lawyers claim Mr Irvine was obsessed with 19-year-old Nicole Healy and stalked her boyfriend, Mr Taska, when he warned him to stay away from her.
Mr Irvine, who had flown to California for drugs treatment, is alleged to have scared the pair so much they moved house and abandoned their college courses.
His father, the head of the judiciary in England and Wales and a close friend of Prime Minister Tony Blair, is said to be standing by his son.
'Personal problems'
Mr Irvine is being held in Orange County Central Jail in California and faces up to 15 years in prison if he is found guilty of the charges against him.
The six charges against him also include having a concealed weapon and breaking into a car.
A spokesman for the Lord Chancellor's Department said: "Alastair's family are supporting him in his current problems as they always have.
"Beyond that they have nothing to say about Alastair's personal problems. The US legal process must take its course in the normal way."
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