While Kennedy cousin Michael Skakel awaited his fate during his trial for the murder of Martha Moxley, the rest of the Kennedy clan abandoned him in a united family snub of the man who betrayed their secrets.

Skakel — the nephew of family matriarch Ethel Kennedy — had boasted that the charismatic Kennedys would be supporting him in front of the jurors. But throughout four weeks of court proceedings, the Kennedys were no-shows!

“The Kennedys have washed their hands of Michael. They don’t want to be pulled into this,” said a family insider. “Michael has betrayed the Kennedy family time and again.”

Finally, during closing arguments, a single Kennedy showed up for half a day. Robert F. Kennedy Jr. left during the lunch break without speaking to reporters.

In 1997, Skakel went to the district attorney in Norfolk County, Mass., and blew the whistle on Ethel and Robert Kennedy’s son Michael for having an affair with his teenage babysitter.

The revelation ended Michael’s marriage to Frank Gifford’s daughter Victoria.

The scandal also ended the gubernatorial campaign of Skakel’s cousin Joseph Kennedy.

Still, Robert Jr. and brother Douglas Kennedy made a brief appearance in support of Skakel during hearings in June 2000 to decide if the case should be heard in juvenile court.

And Skakel — who according to court testimony boasted that he could get away with murder “because I am a Kennedy” — was counting on continued support from the Kennedys.

Skakel attorney Michael Sherman even hinted before the trial that 74-year-old Ethel would travel to the courthouse in Norwalk, Conn., in support of her nephew.

But the Kennedys stayed away after they learned that Skakel, 41, was planning to cash in on a tell-all book revealing more Kennedy secrets.

Although the book was never published, several sections were posted on the Internet on many of the Martha Moxley sites. The book proposal hailed it as, “The first account by an insider of the avarice, perversion and gangsterism of America’s Royal Family.”

The insider added: “It breaks Ethel’s heart that her nephew has created so much pain for the Kennedy family.

“The Kennedys don’t wish him any ill will. But they will not stoop to help him either.”