Since 1927, the lower Mississippi has not burst the levees, although it came dangerously close in 1973 and 1997. But containing the river had an unintended consequence. Previously, the river had deposited so much sediment that it actually created all the land from Cape Girardeau, Missouri, to the Gulf of Mexico. With the levees preventing periodic flooding, the sediment no longer replenished south Louisiana. And the land began to sink, making it more vulnerable to hurricanes. The loss has been greatly worsened by pipelines and shipping channels that cut through the vast marsh and speed erosion.
The 1927 flood's political and social consequences were possibly even more significant than its environmental legacy. The flood made Herbert Hoover president of the United States. A logistical genius, Hoover had already earned the nickname "the Great Humanitarian" for overseeing the distribution of food in occupied Belgium before the United States entered World War I. After the war, back in the United States, he ran food programs for Europe. In 1927, Hoover was Secretary of Commerce, and President Calvin Coolidge put him in charge of the rescue, care and rehabilitation of nearly a million people. He seized the opportunity. The flood crest took weeks to snake down the Mississippi River, giving the press the chance to cover battle after battle to hold the levees. It made for a bigger story than Katrina. In all of this, Hoover performed masterfully—organizing rescue fleets and displaced persons camps as well as the delivery of food and supplies—and he made sure everyone knew it. "The world lives by phrases," he once said. Portrayed as a hero in papers all across the nation, he confided to a friend, "I shall be the nominee, probably. It is nearly inevitable."
Hoover's presidential campaign began the shift of African-Americans from the Republican Party to the Democratic. The press had created Hoover's candidacy, and a potential scandal was brewing about abuses of—and virtual slavery imposed on—blacks in some of the refugee camps that he oversaw. This would have undermined Progressive support for him, threatening his candidacy.
How could he head off the scandal? There is irony in the answer. Since the South was then solidly Democratic, few whites were active in GOP politics, leaving the party of Lincoln in the hands of African-Americans throughout the region. Although blacks could not vote in most elections in the South, they could do so at the Republican National Convention. Hoover, both to protect himself from the abuse charges and to secure core delegates, in essence reached a deal with the national African-American leadership. He named a "Colored Advisory Commission" to investigate the abuses, and in return for the commission whitewashing the scandals and supporting his candidacy, Hoover promised to break large plantations into small farms and turn sharecroppers into owners. Robert Moton, head of the commission and the Tuskegee Institute, said this would be "the greatest boon to the Negro since emancipation."
The blacks kept their word; Hoover broke his. This very personal betrayal snapped the emotional connection between the national African-American leadership and the GOP, and made it easier for Democrat Franklin Delano Roosevelt to attract black support for his policies four years later.
The 1927 flood also changed the face of many cities. The black migration out of the South had begun in World War I, but slowed to a trickle in the 1920s. In the flood's aftermath, hundreds of thousands of African-Americans moved from the flooded region to Detroit, Chicago, Los Angeles and elsewhere. In the 1930s, this migration dwindled, and did not pick up until after World War II and the mechanization of agriculture.
But the most important and most subtle change generated by the flood involved the way Americans viewed government. Before the flood, Americans generally did not believe government had a responsibility for individual citizens. Consider the yellow fever epidemic that had struck New Orleans in 1905: U.S. public health officials would not help New Orleans until the city put up $250,000—in advance—to cover federal expenses. Americans accepted this. Likewise, when a 1922 flood left 50,000 in Louisiana homeless, Governor John Parker, a close friend of Hoover's, refused not only to tap the federal government for help, he declined even to ask the Red Cross, declaring, "Louisiana has not asked for aid and will not."
Though the federal government in 1927 had a record surplus in its budget, not a dollar of federal money went in direct aid to any of the one million flood victims. (Hoover established private reconstruction corporations—they were failures.) The only money that the U.S. government spent was on supplies and salaries for military personnel who participated in the rescue.
But Americans believed that the federal government should have done more. John Parker, no longer governor but then in charge of helping the 200,000 homeless in Louisiana, reversed himself and desperately sought all the outside help he could get. Across the nation, citizens demanded that the federal government take action. The sentiment became concrete a year later, when Congress passed the 1928 Flood Control Act, a law that would cost more than anything the government had ever done except fight World War I; the law would also set a precedent by giving the federal government more authority to involve itself in what had been state and local government decisions.
Today, many people are wondering if Hurricanes Katrina and Rita will have a similarly large impact on American life. Clearly, they will in some areas. Government on all levels will reexamine its ability to respond. Designers of major projects will give environmental forces a higher priority. Population will shift at least regionally, permanently affecting such cities as Jackson and Houston, not to mention New Orleans, Baton Rouge and Lafayette, and possibly extending to Atlanta and points in between. Political pressure to address global warming will likely increase, since most experts believe that a warmer Gulf of Mexico means, at the very least, more intense hurricanes.