Short Answers

Pat Buchanan: "People that brought down Nixon also resulted in the fall of South Vietnam..."

Well, Pat, I've always felt that South Vietnam fell because you pretended to have a trick knee so you wouldn't have to go.

Rush Limbaugh: "Had they not brought down Nixon, we wouldn't have lost Vietnam..."

Feel free to substitute "butt boil" in the above. Or let me ask you this: why didn't Nixon just go ahead and win the war in his first term?

Rush Limbaugh: "Had [they] not brought down Nixon, the Khmer Rouge would not have come to power and murdered two million people in a full-fledged genocide."

Peggy Noonan: "Nixon's ruin led to a cascade of catastrophic events...the rise of a monster named Pol Pot, and millions--millions--killed in his genocide."

The rise of the Khmer Rouge is directly attributable to the actions of one Richard Milhouse Nixon. His secret bombing of Cambodia made the difficult position of the Sihanouk government untenable, which led to the US-supported rise of Lon Nol, who was both incompetent and corrupt. And the US invasion of Cambodia pushed Vietnamese troops deep inside the country, where they fought Cambodian government forces. Whether there would have been a Cambodian genocide without the American presence in Vietnam, or Cambodia, is moot. That the Khmer Rouge takeover was facilitated by the US presence there, rather than its eventual departure, is indisputable.