At the center of the controversy is an exotic but popular mortgage the Sandlers pioneered that helped generate billions of dollars of revenue at their bank. Known as an option ARM — and named “Pick-A-Pay” by World Savings — it is now seen by an array of housing analysts and regulators as the Typhoid Mary of the mortgage industry.

While Mr. Sandler supported the center’s antipredatory goals, he disagreed with Mr. Eakes’s position on prepayment penalties and sought to change his mind. Mr. Eakes says the Sandlers convinced him to drop his opposition to prepayment penalties.

In the early 1980s, the Sandlers' World Savings Bank became the first to sell a tricky home loan called the option ARM. And they pushed the mortgage, which offered several ways to back-load your loan and thereby reduce your early payments, with increasing zeal and misleading advertisements over the next two decades. The couple pocketed $2.3 billion when they sold their bank to Wachovia in 2006. But losses on World Savings' loan portfolio led to the implosion of Wachovia, which was sold under duress late last year to Wells Fargo.