If you like corny jokes, then Rotary Club meetings are a good place to find them, and on that score, New Orleans Mayor Mitch Landrieu didn’t disappoint during his recent appearance at the Rotary Club of Baton Rouge.

Landrieu opened his speech with an old saw about twin brothers — one an inveterate pessimist, the other, a seemingly incurable optimist. When the child psychologist brings the pessimistic tyke to a roomful of beautiful toys, the child frowns in disappointment, certain that the room’s windfall of treasures will surely break if he tries to enjoy them.

But when the eternally sunny twin is ushered into a roomful of manure, he scales the mound and cheerfully begins digging. “With this much manure,” he declares gleefully, “there’s bound to be a pony in here somewhere.”

“That was Ronald Reagan’s favorite joke,” said Landrieu, a lifelong Democrat. The mayor added that optimism is key in leading cities such as New Orleans, where the mayor’s job is very much like “being an emergency room doctor in a war zone.”

Landrieu’s bipartisan nod toward Reagan acknowledged that regardless of party, voters are generally more galvanized by leaders who appeal to possibility rather than fear.

Reagan knew this, and leaders across the political spectrum would do well to remember that on most questions of policy, the optimist usually wins.