Nixon lied about his party breaking into the office of the dem party in the watergate hotel. He did not lie under oath, and it was an insignificant event that had no impact on the "foundations of the nation" What a stupid thing to say.
There was a lot more to it than that. There was the spying on Americans, the abuse of power, the payoffs to witnesses, all of which Nixon was dumb enough to tape himself doing.
Clinton lied under oath about having sex in the oval office with a girl young enough to be his daughter. He defiled the oval office and then lied about under oath.
First, he never had sex IN the Oval Office. Other rooms, yes.
Second, I doubt he was the first or last president who had sex with a woman other than his wife.
Third, having sex with a woman other than your wife isn't against the law.
Fourth, lying about it in court might be a crime, but most of us would lie in court about that.
I don't know about you, but I would not lie under oath about anything, nor should the president of the USA.