There is no need to ask, "what if" with Johnson. Hurricane Betsy flooded New Orleans during the Johnson administration, and Johnson was in the equivalent of the Superdome (a shelter) personally listening to people and making sure they had water, comforting the poor and dispossessed. This is what a great-hearted, competent president like Johnson, does. This was recalled in a moving NY Times editorial around the time of Katrina:
http://www.nytimes.com/2005/09/24/opinion/24williams.html?ei=5090&en=7d8120725ff18559&ex=1285214400&partner=rssuserland&emc=rss&pagewanted=printSeptember 24, 2005
L.B.J.'s Political Hurricane
By BRIAN WILLIAMS
New Orleans
GIVEN President Bush's final decision not to head to Texas in advance of Hurricane Rita, it's worth noting that American presidents have long found both political riches and peril at the scene of a storm. A listen to the tapes of President Lyndon B. Johnson's White House telephone conversations of 40 years ago reveals that history does indeed repeat itself, even if presidential reactions and motivations have varied widely.
On the evening of Sept. 9, 1965, Hurricane Betsy, a Category 4 storm, roared into Louisiana with winds of up to 160 miles per hour. The next day,
President Johnson followed coverage of the damage, watching the three television sets in the Oval Office and monitoring the news service wires clacking away inside the soundproof cabinet next to his desk. Then, at 2:36 in the afternoon, Senator Russell Long of Louisiana, son of the legendary Huey Long, called the president and urged him to come to New Orleans. Floodwaters had spilled over the levees, and three-quarters of New Orleans was under water.
The senator opened with a geography lesson. "Mr. President, aside from the Great Lakes, the biggest lake in America is Lake Pontchartrain," he said. "It is now drained dry. That Hurricane Betsy picked up the lake and up and put it inside New Orleans and Jefferson Parish." Long said that his own house had been destroyed, but that his true concern was "my people - oh, they're in tough shape."
<snip...Basically, Long pursuaded Johnson to cancel his schedule and fly to New Orleans.>
The presidential motorcade drove down Canal Street, broken store windows lining both sides, and made several stops.
Johnson spoke with bystanders and toured a shelter packed with storm victims. An aide wrote, "Most of the people inside and outside of the building were Negro ... the people all about were bedraggled and homeless ... thirsty and hungry." At one point, a woman rushed up to the president to tell him that both of her sons had drowned. The next day's New York Times reported,
"according to Bill D. Moyers, the presidential press secretary, Mr. Johnson was 'almost overcome.' " He watched the stream of evacuees who had been rescued by boat from the rooftops of their houses and were now on foot, carrying whatever possessions were left.
When another woman asked the president for drinking water, Johnson dispatched a Secret Service agent to make sure it was delivered. An entry in the White House travel diary paints a grim picture:
"Calls of 'water - water - water' were resounded over and over again in terribly emotional wails from voices of all ages." The
president suggested that local soft drink bottlers (in an era before bottled water was an American staple) make their inventory available. Seventy-five people died in the storm, most of them in the city. Hurricane Betsy caused $1.4 billion in damage.