Basically: I committed a crime while trying to stay in office illegally, but you can’t hold me to account because I’m running for office.
Pretty much “I’m a big-deal Republican, so you can’t apply the normal rules to me, even though others have run for President from jail”
That’s an incorrect reading of that phrase. “High crimes and misdemeanors” is a particular term of art that means pretty much the same thing as “conduct unbecoming an officer and a gentleman.” It means someone holding office who, by virtue of using the powers of that office, abused those powers in a particularly impactful way. It doesn’t necessarily mean the violation of a specific law, although it could obviously include that. There’s obviously legal precedent that provides additional context, but as formulated at the time it was written it basically means “abuse of power.”
I expect so since I’m no lawyer, makes me kind of curious what the most mundane reason any of our relatively few impeachments where for. Even the first of Trump’s I don’t know would truly fit an existing criminal law without some work, more just acting like a tool against the interests of the nation.