THE defenestration of Vikram S. Pandit from the corner office at Citigroup might just be a turning point for shareholders of this great big beleaguered bank. What remains to be seen, however, is whether the change will also protect American taxpayers from future bailouts.

There are many positives in Mr. Pandit’s exit, beginning with the indication that Citi’s directors have finally woken up. No more snoring in this sumptuous boardroom, perhaps.

By appointing Michael L. Corbat to take over as chief executive, the board seems to have recognized that this bank should be overseen by, yes, a banker. Not a lawyer (Charles O. Prince III) and not a hedge fund manager (Mr. Pandit).

Given Citi’s close ties to Washington, we can only hope that the change of command also reflects a regulatory prodding to overhaul the company. And if that involves cutting this behemoth down to a manageable size, then taxpayers should definitely cheer.