Mr. Rangel, clad in a gold tie clip, opal rings and a colorful handkerchief, intends to bring more than a change in style to the chairmanship. Experts in tax policy predict that if the Democrats win, Mr. Rangel will radically change the way the federal government levies America’s wealth.

“He has been waiting a very long time for this,” said Thomas E. Mann, a senior fellow in governance studies at the Brookings Institution. “I’d expect him to have a very active agenda”...

Still, Mr. Rangel—whose power derives from his role as the gatekeeper to most of the government’s tax legislation—is relishing the chance to abolish some of Mr. Bush’s key tax legislation and initiatives.

As Ross Eisenbrey, vice president and policy director of the left-leaning Economic Policy Institute, put it: “If Charlie Rangel doesn’t want it to happen, it won’t happen"...

One area where he is likely to be active is on the alternative minimum tax, which was originally created to ensure contributions to the federal coffers from wealthy Americans who paid little or no taxes due to many deductions. Mr. Rangel wants to readjust the burden to exempt the middle-class families who have come to be burdened by it, and to cover the cost by closing loopholes for corporations who move their headquarters into foreign tax shelters.

“There is not one damn Republican who is going to say that’s fair,” said Mr. Rangel, anticipating the fight he’s going to wind up having.

He also plans to revivify the enforcement abilities of the I.R.S. to bring in billions of uncollected dollars. He intends to demand the insertion of more labor and environmental protections into America’s trade agreements. And he plans to increase the power of the government in negotiating prices for pharmaceutical purchases, and to limit access to the health savings accounts, created by President Bush’s 2003 Medicare bill, which were designed to help Americans put money away for health expenses on a tax-free basis.