Grant wrote:
I wonder how many times that was done while he was president. I know that the warden in "Pardon Us" with Laurel and Hardy is an obvious FDR parody. The face as well as the voice, and even one of his lines -
"My boys - and you are my boys...."
  
Wilfred Lucas may have been imitating FDR in L&H's PARDON US, but the movie was shot in 1930, previewed in August 1930 and released in August 1931, which was almost a year before Roosevelt was nominated for President. I don't know if then New York Governor FDR's radio voice was that well-known nationally enough to rate an impersonation in a Laurel & Hardy comedy.