There was an All-Star Squadron Annual (#3?) that featured a slew of presidents; the JSA was assigned to save them from assassination to prevent the disruption of the timeline. Since it was the 40s, this meant saving not only FDR and Truman but also JFK and Nixon as young Navy officers, Eisenhower when he was still Commander of Allied Forces and Ronald Reagan while he was making movies for the Army. Not sure where Carter or Ford were, but they were in there. (For the record, the heroes didn't know these were future presidents, just that they would be somehow crucial to history.)
Green Lantern suffers a major career failure when he's unable to save a kid from a falling tree (because...duh...it's made of wood!). The kid is never identified, but it's implied he would've followed Reagan in the office (the story was written when Reagan was still serving).
Depending on your politics, this can be either a confirmation that America's been off the track since Reagan stepped down, or perhaps proof that Clinton, Bush I and/or II or Obama were never "meant" to get the job (take your pick based on your bias). But from a DC comics perspective, it suggests that the comic book world did indeed get the same set of 20th century presidents we did, despite evidence to the contrary (eg: "The President of Steel":
http://supermanfan.nu/main/?p=2463)
Of course, considering it's the JSA, maybe it just means that
Earth-2 got all "our" presidents, even if Earth-1 didn't.