John Thune

Who he is: Former congressman who beat Tom Daschle.

What he wants: Tax cuts and health care deductions for the self-employed.

Who backs him: Blank Rome, a corporate law firm known for political contributions, mostly to the GOP; Fresh Express, the Salinas, Calif., bagged-salad company; and Arent, Fox, a large New York and D.C. law firm.

What else: Thune, one of the Senate's highest-profile newcomers, worked at the SBA under Reagan.

David Vitter

Who he is: A former corporate lawyer.

What he wants: Association health plans, health savings accounts, tort reform, and the elimination of the estate tax.

Who backs him: Louisiana-based shipbuilders Edison Chouest Offshore and Bollinger Shipyards; New Orleans law firm Jones Walker; and Louisiana real estate magnate Joseph Canizaro.

What else: Vitter also serves on the committee on the environment, where his key issue is fighting coastal erosion.

John Cornyn

Who he is: Former Texas attorney general and state judge who, in private practice, defended malpractice suits.

What he wants: Lower taxes, less red tape, fewer "junk" lawsuits, and association health plans.

Who backs him: Big donors include Bass Brothers Enterprises; SBC Communications; and Locke Liddell & Sapp, the large Texas law firm.

What else: Cornyn serves on the Budget Committee, so he can help businesses there, too.

Johnny Isakson

Who he is: Former owner of a realty business.

What he wants: To reduce regulation, lower health care costs, and make bonus depreciation and increased expensing permanent.

Who backs him: Real estate interests, including Cendant, Colorado-based Re/Max, and Atlanta law firm Troutman Sanders.

What else: "Government can, with the best of intentions, cause the worst of problems," he told Inc.

Olympia Snowe

Who she is: Committee chair and one of Congress's leading moderates.

What she wants: Association health plans, and restoration of cuts for SBA programs such as women's busi-ness centers and microloans.

Who backs her: Credit-card giant MBNA, a backer of the bankruptcy bill, which Snowe supported; AFLAC, the Georgia-based insurer; and Union Pacific.

What else: She also sits on the Finance Committee.

John Kerry

Who he is: The committee's ranking minority member.

What he wants: Stable funding for the SBA's training programs and women's business centers; business development initiatives in disadvantaged urban and rural areas.

Who backs him: Media, finance, and technology giants like Time Warner, Goldman Sachs, Citigroup, and Microsoft.

What else: Like him or not, his presidential bid helped raise the committee's profile.