The equity firms counter that banking desperately needs cash if the economy is going to recover, and that they are the only big sources of money around. An executive at the Carlyle Group said the industry had an estimated $400 billion in “dry powder,” or ready-to-invest reserves.

To push their case at the White House, the Treasury and the Fed, Mr. Flowers and others in his industry have enlisted an all-star cast of advisers, lobbyists and lawyers. They include H. Rodgin Cohen, chairman of the Sullivan & Cromwell law firm and Wall Street éminence grise, and Randal K. Quarles, a managing director of the Carlyle Group and a Treasury under secretary in the administration of President George W. Bush. Part of their strategy, Mr. Flowers said, is to persuade the Treasury secretary, Timothy F. Geithner, to pressure the Fed to back down.

“Chris is obviously a get-it-done type of person  and he wants to get this done,” said Mr. Cohen, who represents Mr. Flowers. “He believes, as I do, that it is unfortunate to deprive the banking system in the United States of this key source of capital.”

While they press their case, the firms have found some ways around the rules.

They have formed so-called club deals, in which teams of private equity firms and other investors each buy up to the legal limit of a bank  about a quarter or a third, depending on the type of bank  with their individual pieces adding up to 100 percent control. IndyMac, the failed California bank, was sold by the Federal Deposit Insurance Corporation last fall to one such club, which includes funds controlled by Mr. Flowers; the hedge fund billionaires George Soros and John Paulson; and Michael S. Dell, founder of the Dell computer company. The investors are barred from acting in concert to, in effect, take control of the bank  an unwieldy arrangement but one that regulators insist they can enforce.

As part of the IndyMac deal, the F.D.I.C. agreed to take most of the risk from future losses on loans acquired by the partnership  leading Mr. Flowers to quip at one investor forum in New York in January that “the government has all the downside and we have all the upside.”

Mr. Flowers has come up with another way around the restrictions. There is no limit on an individual’s taking over a bank, so he purchased all of the First National Bank of Cainesville in his own name and with his own funds. But that deprives him of the billions his equity firm has set aside to buy banks, so his new bank sits in this tiny town, waiting for a change in the rules.

First National  whose second story is boarded up and whose $17 million in assets are worth about a third of what Mr. Flowers paid for an Upper East Side town house in 2006  seems an unlikely launching pad for a new American banking empire.