I’ll quote from the last few paragraphs of Matthew Yglesias’s post on Vox:
On one level, “Donald Trump doesn’t know what he’s talking about” is the ultimate dog-bites-man story of the 2016 election.
But that’s why I think it’s useful to try to purge yourself of your existing knowledge of the campaign. If you just tuned in Monday night expecting to see two well-qualified and broadly competent candidates discussing the issues in some kind of recognizable shape, you would find yourself sorely disappointed.
The conceit of the Trump campaign is that he’s a smart, business-savvy outsider who can fix things. But he clearly has no idea how to fix things. He doesn’t even seem to have a grasp of what the problems are.
If you were just tuning in to this campaign, you would find yourself hung up on a pretty obvious question — why did the Republican Party nominate a guy who clearly doesn’t know what he’s talking about? It’s a good question.