Nelson Rockefeller vs. Ike re. Lunar Orion

"...Suddenly, the whole nation seemed to want an American to land on the lunar surface. Only a week earlier, Nelson Rockefeller, who was running for governor of New York under the GOP banner, enthusiastically told Eisenhower that if the United States used nuclear explosions for propulsion, a vehicle could be launched that would fly to the moon and return. Rockefeller predicted that it would be "the most notable accomplishment of our time." Later, Eisenhower scoffed at the proposal. "Some people think there are no limits to the amounts of money available for every conceivable project."

From Race to the Moon:America's Duel with the Soviets by William B. Breuer