After Hurricane Katrina came ashore nine years ago today, on Aug. 29, 2005, Louisiana discovered how much it needed America, and America learned how much it needed Louisiana.

Levee breaches after Katrina left New Orleans underwater for weeks, an epic disaster that required massive national intervention. Although Louisiana residents often like to think of the state as a world apart, Katrina reminded us of our deep connection to the rest of the country — and, indeed, the rest of the globe. That bond sustained Louisiana, as people across the planet offered us help.

Such generosity was inspired by deep affection for Louisiana, but pragmatism, too. Seeing an iconic city almost completely submerged, most Americans seemed to realize that an America without New Orleans would be unthinkable. Federal investment in the massive recovery effort, although plagued by bureaucratic inertia, stabilized the Crescent City, helping it attract the private investment required to rebound.

Critics balked at the billions in tax dollars needed to help Louisiana recover. But only three years later, as the global recession of 2008 threatened to throw America’s economy into complete collapse, national leaders approved a much larger relief package to keep the United States strong. Katrina’s devastation prepared the country to face a simple political reality. Even in an age of suspicion about activist government, Congress and the president must sometimes act boldly to do what the private sector cannot handle alone.

Katrina yielded other lessons that have saved lives and property in other places far beyond Louisiana. The storm made Louisiana into a laboratory of disaster response and recovery. Millions have learned from the successes and mistakes in answering the epic destruction left in Katrina’s wake.

We remember, as the recovery effort coughed and sputtered, the snickers of those who blamed the sluggishness of Louisiana’s rebound to some unique deficiency in our culture. But subsequent disasters, such as a massive typhoon in Japan and an East Coast superstorm named Sandy, brought many of the same problems we experienced here. Perhaps others are discovering what Louisiana residents learned long ago: Disasters are inherently messy, confusing and chaotic. That’s why they’re called disasters.

But we take no satisfaction in the prospect of someone having to confront that difficult lesson. We don’t want anyone to suffer the pain that Louisiana residents experienced after Katrina.

Nine years later, some of that agony persists. Wind and flooding washed away homes, business and churches in an instant, and the loss of life left holes in families no passage of time can ever fill.

But amid the loss, we take comfort today in the simple miracle of our endurance. Katrina broke our hearts, but not our spirit — a reminder that the darkest chapter of our state’s history was, paradoxically, also the brightest.