If you take just the suborning perjury and the personal lying and compare them to Nixon and Clinton, Trump is far and away worse. In Nixon's case, he was, in many ways, a decent President for a Republican - horrid with the war, but pretty good foreign affairs and domestic issues. Like Trump, he had a testy relationship with the press, but overall he played a typical role. The original Watergate burglary was, in retrospect, not that awful by current standards. Basically the equivalent of hacked emails, if that bad. And the "cover-up" was largely garden-variety denial lying. So yes, Nixon did it, but in retrospect it was fairly low-level crime. It was just so awful by the standards we thought we had for a President. In Clinton's case, he did it, too, but it the charge was obviously just a technicality so they could railroad him. But in Trump's case, the suborning perjury, lying, etc. is not the best charges that could be available - they're really just a minimum. So for Clinton, you have a guy driving a bit over the limit but you're afraid you can't get a conviction on that so you charge him with driving with improper equipment because of the tail light you broke, and then charge him with assault on an officer because he yells about the light. With Trump, you have a guy who's driving drunk at 130mph, runs over people, smashes police cars, and farts in the general direction of everybody and you agonize over whether you can charge him with disorderly conduct.