Washington divorce attorney Rita Bank has been litigating unhappy break-ups for more than a quarter-century. But next month, the family law heavyweight will find herself in court over an unamicable split with a renowned former client.

Bank is facing a $5 million legal malpractice lawsuit from Nobel laureate Joseph Stiglitz, who is claiming that Bank botched his divorce, gave him counsel that left him financially vulnerable in the proceedings and failed to promptly tell him about merger discussions she was having at the time with his ex-wife’s attorney.