ON Tuesday, the Senate Banking Committee gave Mary Jo White, President Obama’s choice to lead the Securities and Exchange Commission, a rousing show of support, voting 21 to 1 to send her nomination to the full Senate for a vote. Ms. White, who is likely to be confirmed as the S.E.C. chairwoman, will need that bipartisan backing as she takes on a host of challenges at the nation’s top financial regulator.

But if she really wants to make a difference, Ms. White, a former federal prosecutor, should tap into some of that good will in her first days in office and push forward a vital proposed rule on corporate disclosure that the S.E.C. has been considering for over a year and a half.

The reform, suggested in a petition to the S.E.C. by 10 legal scholars in August 2011, would be simple: it would mandate that publicly held corporations disclose their political spending. In the months since the petition was posted, the commission has received nearly half a million comments on it — more than on any other issue in its 79-year history — that have been overwhelming in favor of the proposal. (Typically, S.E.C. rule-making petitions get fewer than 100 comments.)

But despite this broad support from the investing public, experts in securities law, institutional money managers and numerous public officials, the S.E.C. has yet to write an official rule on which the commission can actually vote.