Let’s say you got a divorce. As part of the divorce agreement your ex agreed to leave half of his estate to your kids. He dies. He leaves a will that doesn’t comply with the agreement – leaving 90% of his estate to his second wife. What happens? Enforce the contract you say, the kids get half. That’s what you and I think the answer should be. Maybe you have a divorce settlement with a similar provision. Will it hold up? That is the issue that has been tying up the Oleg Cassini estate for years.

Oleg Cassini, the fashion designer who made first lady Jackie Kennedy’s style the "single biggest fashion influence in history" died in 2006. Jackie had chosen Oleg Cassini as her exclusive couturier and called him her "Secretary of Style."

Cassini married film star Gene Tierney in 1941. Tierney, a very successful actress, was nominated for an Academy Award for her performance in "Leave Her to Heaven." (The story is the basis for the plot in Agatha Christie’s murder mystery, Mirror Crack’d.) Tierney and Cassini had two daughters, Christina Belmont and Daria Cassini. When Tierney was in her first trimester of pregnancy carrying Daria, a fan with German measles broke her quarantine to shake hands with her favorite star, and Tierney unknowingly contracted the disease. Daria was born deaf, severely retarded and nearly blind.

When Cassini and Tierney divorced in 1952, the marriage termination agreement mandated that half of Mr. Cassini’s estate be split equally between the couple’s two daughters upon his death.

Marianne Nestor married Cassini in 1971, and remained his wife until his death in 2006 at age 92. Their marriage was a secret for over 30 years. Cassini’s own daughter did not know he was married until she went to see him on his death bed, to discover he had already passed and that his "wife" – news to the daughter – had left orders forbidding the daughter from viewing the body or informing her as to where the body was removed.

Cassini’s will provided $500,000 in trust for his daughter Daria and $1 million to his daughter Christina. The rest, estimated at $50 million, went to the widow, Marianne Nestor.

Christina sued the estate in February 2007, demanding 25 percent of her father’s estate based on the agreement reached with her mother when they divorce in 1952. The Cassini/Tierney divorce agreement provided: "Husband agrees that he will by testamentary disposition leave not less than one-half of his net estate, after payment of debts and taxes, to Daria and Christina in equal proportions."

Marianne claimed that the provision is unenforceable, having been made more than 60 years ago. (Does that matter? Isn’t a contract a contract?) Marianne claimed that the provision giving half of Cassini’s estate to his two daughters was unenforceable or at least limited to the amount of his estate at the time of the 1952 divorce. Christina argued she was still entitled to 25 per cent of her father’s estate under the divorce agreement and filed a claim in Nassau County Surrogate’s Court in 2007.

In May 2012, a New York appeals court finally awarded Christina her entitled $13 million – a quarter of her father’s estate. She has received nothing since her father died and still gets nothing as the verdict is appealed. It would seem that, the other daughter, Daria, would also be entitled to 25 percent or $13 million. Daria died in 2010.

Unhappy with the award of $13 million to Cassini’s daughter, Marianne Nestor has filed an appeal and another lawsuit. She is suing Putney Twombly Hall & Hirson, in New York, two of its attorneys, William Pollak and Philip Kalban, and also Nachsin & Weston, of Los Angeles. Her new lawyers say that her old lawyers (the ones being sued) should have challenged Christina’s 2007 claim under the statute of limitations. Their failure to do so was an act of "negligence and malpractice." She is seeking $13 million. According to Condé Nast, the lawsuit remains unresolved.

In the suit against the old lawyers Marianne Cassini is represented by Douglas Eisenstein, with Carroll McNulty & Kull. (Could they be defendants in the next lawsuit?)

Andrew W. Mayoras, an estate litigation attorney and co-author of Trial & Heirs: Famous Fortune Fights, is reported by ABC News as saying that he doubts Marianne Nestor will win. "In this case, it appears that Marianne Nestor Cassini, having failed in both New York and California — both in the initial courts and the courts of appeal in each state — now seeks to lay blame on the only target left," he said. "She feels they should have attacked Christina Cassini’s claim on the basis that it was filed it too late. But, it appears that she filed it approximately one year after her father died. Until he died, the divorce judgment provision was not breached because he could have created a will that complied with it. So Christina’s claim likely will be determined to be timely and it is very unlikely that Nestor’s claim will prevail."

The moral of the story: Don’t be so sure that a contract signed by your divorcing spouse will be enforced later. And if you’re a lawyer – be prepared to get sued if your client, the second wife, doesn’t get what she wants.

Vanity Fair, a Condé Nast publication, ran a feature in 2010 titled "Cassini Royale" about the battle over the estate. Many details of the dispute and of Cassini’s and Marianne’s lives were revealed. In August 2011, Marianne Nestor countered by suing the magazine and Maureen Orth, the article author, for $10 million in damages for libel and slander. According to the Atlantic Wire, Vanity Fair declined to comment, citing pending litigation. In the article, Orth notes that Marianne has been involved in "at least 15 lawsuits. . . in the last two decades, including one brought by her neighbor, Neil Diamond over an obstructed view.