Al Smith
Al Smith was New York governor for 4 terms and ran for President in 1928, losing to Herbert Hoover.
During his presidential bid, strong attacks were leveled against him because he was Catholic. He was, in fact, the first Catholic Presidential nominee. There was concern that he would answer to the Vatican instead of following the Constitution. Some took this fear so far as to believe that the Pope would pack up the Vatican and move it to Washington DC. A joke that appeared after the election was that Smith sent a one-word telegram to the pope upon his loss, saying "Unpack." The United States would not overcome its fears for thirty years, when it elected Catholic John F. Kennedy.
Speech Relevance
In 'A Time For Choosing', Reagan says:
Back in 1936, Mr. Democrat himself, Al Smith, the great American, came before the American people and charged that the leadership of his party was taking the party of Jefferson, Jackson, and Cleveland down the road under the banners of Marx, Lenin, and Stalin. And he walked away from his party, and he never returned to the day he died, because to this day, the leadership of that party has been taking that party, that honorable party, down the road in the image of the labor socialist party of England.
Reagan is talking about a speech given on January 25, 1936 in Washington DC. It has since gone on to be called the Betrayal of the Democratic Party. The speech can be found in its entirety in the Appendices of the book The Naked Capitalist.
The exact quote from the speech Reagan is paraphrasing is as follows:
Now, it is all right with me. It is all right to me if they want to disguise themselves as Norman Thomas or Karl Marx, or Lenin, or any of the rest of that bunch, but what I won't stand for is to let them march under the banner of Jefferson, Jackson, or Cleveland.
Smith did run as a democrat for his governor and presidential candidate. It wasn't until after the 1932 that he seemed to sour on the democratic party. He actually campaigned for the Republicans in 1936 and 1940.