Why Santorum deliberately chose the only man of the forty-three men who have served in the White House that actually paved the way for a Santorum candidacy is a quandary. Does he think attacking John Kennedy the Democrat helps him with the ultra-conservative base he's courting? If so, one could hope that his misrepresentation of Kennedy's words was simply a mistake. Unfortunately, more and more the Republican Party is demonstrating that facts are of no importance. Personally, I highly doubt Santorum 1) thought anyone would take the time to read Kennedy's speech from 1960, and 2) actually thought it mattered if he was truthful in his representation of Kennedy's words. It's far easier to use a person's words in a way that helps whatever point you are trying to make than to use a person's words in the actual way they intended them.
Words without the benefit of context are so easily distorted. For example, the portion of Kennedy's 1960 speech to the Greater Houston Ministerial Association that Santorum quoted consisted of: "I believe in an America where the separation of church and state is absolute." It was the absolute part that Santorum said made him "almost [throw] up." But Santorum failed to finish President Kennedy's quote. The sentence, rather than ending at 'absolute', continued on to say, "where no Catholic prelate would tell the president (should he be Catholic) how to act, and no Protestant minister would tell his parishioners for whom to vote." Kennedy was walking a fine line with an electorate that feared the influence of the Vatican. He wasn't giving a speech to limit the religious from the "public square" as Santorum accuses. Kennedy was trying to open a door for himself in the public square, a door that fifty-two years later Santorum is perfectly happy to walk right through. To call Santorum ungrateful would simply be too kind.
Did Santorum distort Kennedy's words and, in effect, history because he wants to be the edgy candidate who attacks Democrats (dead ones even) or was this just another Santorum stunt on his quest to prove himself as the extreme social conservative in the race? In any event, Rick Santorum stands by what he said on ABC's This Week.