I would posit that Trump is not a worthy opponent. He does not use facts and reason for his arguments. He uses bullying and lies, that makes him "unworthy" in my eyes.
But in terms of political discourse, that's about as "worthy" as it gets. People have been trained by different (mainstream) politicians over the years that lies are the new normal, facts don't matter, promises are empty, etc. It's no wonder that eventually an extremist would succeed with a much more blatant version if those basic strategies.
If you get flagged for deliberate trolling, that's not proving the point of the article. Trump refuses facts. It doesn't matter whether you think he got to the right or wrong viewpoint, he is objectively not a worthy debater. He does not explain why you should think something, back it up with true statements, and meaningfully respond to counterpoints and criticism.
I don't care what you voted, but you have not named a 'worthy opponent' for didibus.
At the very least, you can't be a demagogue, that is someone who makes use of popular prejudices and false claims and promises in order to gain power. This goes for all sides btw.
Ideally too, especially if you're to speak at a well respected university, I'd like you to have some credentials, a book, research, a strong presence in existing circles related to the problems you'll address, etc. Something that indicates you've spent a good amount of time (like above the 90th percentile) thinking this through by yourself first, and by a few others.
It's for that reason that I don't think we should prevent anyone from speaking. The only solution is more speech.
Also: Universities are doing a pretty poor job of bringing in certain kinds of speakers. If you want change, make it.