Your dad was right. Nixon's mistake was that in trying to protect his friends he obstructed justice. He should have simply stepped aside and let the investigation run it's course. The political gameness of Watergate brought down a president. Today it is bringing down a nation.
Nixon was a perfect example of the Peter Principle.
He'd have never found himself in the Whitehouse had he not been Ike's Veep.
He was an accident of history, much like the Bush dynasty.