GLENN HUBBARD is the most influential chairman of the Council of Economic Advisers in two decades. His job is to provide economic analysis for the White House, primarily on domestic issues such as taxes and jobs. The sudden popularity of eliminating the taxability of stock dividends–that’s Hubbard’s doing. As a young U.S. Treasury Department official ten years ago, he circulated a fifty-page study advocating the change, and he followed up this year by prevailing on President Bush and his senior aides to support the idea. And Hubbard was also active in feeding information and analysis to the presidential commission that looked at one of Bush’s pet projects, reforming Social Security and creating individual investment accounts.