He got one part right, even if the wording was wrong. Governors are normally elected President, not Senators. Warren G. Harding and John Kennedy were the only sitting Senators who were elected to the White House.
But what about Non Governors. Eisenhower. Truman was a Senator 1 year before FDR died. LBJ was a powerful Senator.
Nixon was a Senator. Taft was a senator. Granted they were not Senators when Elected but I need more Coffee sorry.