By John Henry A casual conversation about Franklin Roosevelt’s life-changing struggle with the polio virus included a question from a learned companion.“Now, did he contract that as a child?”It’s one of a number of many.Few know of the circumstances surrounding FDR’s exposure to the virus and its devastating effects, which left the once robust man from New York’s other Roosevelt family without the use of his legs and put his almost certain climb to the nation’s highest office in jeopardy.If it had been up to his domineering mother, the man whom many consider to be among the country’s best chief executives would have retired to comfort in Hyde Park, N.Y.In what turned out to the benefit of history, FDR defied the wishes of his mother and persevered.It’s a topic explored by Miami University professor James Tobin, who in The Man He Became: How FDR Defied Polio To Win the Presidency examines what is new ground for many about the decade leading up to Roosevelt’s election as the country’s 32nd president.It was a journey many never dreamed would happen after FDR’s trip to Bear Mountain, a campground where the future president, by that time a 39-year-old up-and-comer after being nominated to be vice president by James Cox in the lost 1920 election against Warren Harding, made a trip to visit Boy Scouts.It was there that FDR was exposed to the virus, likely through a handshake with one of the boys.Only a fraction — about 1 percent — of those exposed suffer the debilitating effects Roosevelt encountered.