The gears of government tend to grind slowly. But in Wisconsin lately they are racing at turbocharged speed.

Mr. Singer, professorial and soft-spoken, used a gathering of business and government leaders at the conservative Manhattan Institute to lash out at indiscriminate attacks by political leaders against anything that moves in the world of finance. Government efforts to take over and run the economy through more regulations, he warned, threatened to ruin the United States standing as the world leader in finance. As the head of a $17 billion hedge fund, Mr. Singer, a self-described Barry Goldwater conservative who is 66, is using his financial might to try to change those policies. He has become one of the biggest bankrollers of Republican causes, giving more than $4 million of his money and raising millions more through fund-raisers he hosts for like-minded candidates who often share his distaste for what they view as governmental over-meddling in the financial industry.