Meh, I think it's entirely asymmetrical in this era. Democrats aren't good for much, but they're very good at respecting norms.
Trump is willing to do completely unprecedented, vindictive, and malicious things because he's so popular with so many people who are either checked out, nihilistic, corrupt, or just completely unconcerned about the concept of good governance.
It's not a pendulum where there's some super-corrupt Democrat waiting in the wings to do the same things upon their enemies, this really is the Republican party openly embracing kleptocracy and lawlessness.