The shaping of the U.S. financial reform bill has given a new meaning to the old market adage "Don't Fight the Fed."

Five months ago, many lawmakers wanted to confine the U.S. central bank to setting monetary policy and acting as a lender of last resort for banks.

Blaming the Fed for missing the warning signs in the run-up to the financial crisis, senators were preparing to step up their scrutiny of the central bank and strip its authority to examine and supervise all banks.

But fierce lobbying by regional Fed bank chiefs and hundreds of small commercial banks scattered across the country persuaded Congress otherwise.

In a lopsided 90-9 vote on Wednesday, senators approved an amendment to a regulatory reform bill that would preserve the Fed's power over small state-chartered banks instead of moving them to another banking regulator.

It was the second time in as many days that the U.S. central bank scored at least a partial victory. On Tuesday, the Senate approved an amendment for a one-time audit of the Fed's emergency lending during the latest financial crisis, though some senators had initially wanted to subject the central bank to repeated reviews.

"The Fed has been working pretty strenuously to oppose" the broader Fed audit and restrictions on federal bank oversight, said Gerald Blanchard, who advises financial firms for the Bryan Cave law firm.

Although the Fed has been blasted for rescuing troubled Wall Street firms such as Bear Stearns and AIG and not doing enough to rein in subprime lending, senators recognize that the central bank played a role in keeping the financial system intact.

"There are a lot more people that realize the financial crisis could have gotten a lot worse without the Fed," Blanchard said.

The Senate's legislation must eventually be merged with the House of Representatives' bill, which includes a provision to subject the Fed to more audits.

This week's two-part win for the Fed comes about two months after the central bank won other concessions from lawmakers who wanted to strip it from supervising any banks, including the largest, to leave it to focus on its core monetary policy mission.

Fed officials had strategized for months on how to get their message across. Ernie Patrikis, a former vice president at the New York Federal Reserve bank, said Wednesday's vote shows "great work done by the presidents of the Federal Reserve banks.

"They were really bringing the word home that doing this would make the Fed the central bank of Wall Street. That was the message to lawmakers. You are taking the Fed from the roots around the country," said Patrikis, now in private practice at White & Case LLP.

Ever since Christopher Dodd, the Senate's architect on financial regulation, introduced a bill to overhaul Wall Street, Fed officials have been pressing their case.

In countless meetings with lawmakers, newspaper editorials and in speeches across the country, they have stressed the importance of their supervising smaller banks.

Fed bank presidents, including Jeffrey Lacker from Richmond and Charles Plosser from Philadelphia, argued stridently that the information the Fed gleans from small bank supervision helps it formulate monetary policy.

Kansas City Fed chief Thomas Hoenig has been particularly vocal about the risk that removing small bank oversight from the Fed would centralize power in New York and Washington. The fight for the Kansas City Fed was particularly personal: the provision would have left it with no banks to supervise.

Hoenig also wrote an opinion piece in the New York Times titled: "Keep the Fed on Main Street" and went on cable TV channel C-SPAN to take questions from Americans on Main Street—a rare step by a Fed president and testament to the scale of the outreach efforts.

Supporting the Fed were hundreds of community banks and their lobby group, the Independent Community Bankers of America. The association sent letters and made personal visits to every senator with the same message: The Fed would be much more effective if it had the window into the entire national economy that its supervision of community banks can provide.

"Our efforts have helped. The Fed Reserve banks made a strong case, Fed Chairman Ben Bernanke made a strong case," said Steve Verdier, senior vice president at the ICBA.

"It demonstrates that grass-roots appeal has a lot of impact on Congress and powerful ideas expressed by the Fed and presidents of the Federal Reserve do have an impact on Congress," he said.

The financial services industry is now targeting a provision in the Senate's bill that would strip the Fed of its authority to write rules for consumer financial products such as mortgages.

That battle, however, may be one too many. It would pit the Fed against the Obama administration, which has proven an important ally in every other fight.