That's what makes him almost the worst imaginable person to be a Presidential candidate, let alone his Party's nominee, let alone actually serving as Head of State to the most powerful nation in the world. Just the reality of this man travelling around the country stoking up violence and hatred everywhere he goes is already making his candidacy something pretty close to a security threat.
But that's not even the most fundamental reason why Donald Trump would be a unprecedentedly terrible President.
The most fundamental reason is that he has no interest in, capacity for, or understanding of any of the elements of actual job description for "President of the United States".
You can get an early glimpse of how profoundly true this is, by reflecting on this fact:
His team are losing delegates because the don't understand how the delegate selection process works.
In a number of states, and in a number of different critical ways, Team Trump has been spectacularly behind the ball on actually securing delegates. For background - you need to know that winning a state primary or caucus is only step 1 of the Democratic Delegate selection process. Step 2 is getting your supporters elected to fill those pledged delegate seats in state party conventions.
But Trump has not got his eye on this ball.
In Colorado, they forgot to tell their supporters which delegate candidates to vote for, and it cost him delegates.
In Illinois and Texas, Trump supporters refused to vote for Trump-supporting delegate candidates with minority names, costing him delegates.
And in many other states, Team Trump doesn't seem to have showed up to the party conventions, leaving supporters of other candidates to be elected as delegates - which matters enormously because although they are pledged to vote as per the statewide vote on the 1st ballot, they can do whatever they like on the 2nd. It will cost him delegates.
To be fair, the Democratic Party Delegate Selection process is hard work. It's a byzantine, complicated process rife with insider-y rules and obscure pitfalls.
But you know what? So is the Presidency. In fact, that's MOSTLY what the Presidency is. Most of that job is about appointing a Deputy Secretary of Agriculture who will submit annual reports in compliance with Congressional Mandates. It's on very rare occasions about taking bold moves to shake up the international system, but far more often it's about carefully calibrating your foreign policy organisation to not pointlessly offend an ally or unintentionally trigger tariffs against our imports. On a good day, it might mean opening up markets to more of our goods, or moving forward a piece of legislation that furthers your agenda.
But most of the job is... a JOB. A management task, that requires leadership of a detailed, highly constrained, limited organisation (the US Federal Government) that operates in this way precisely because it is massive, because every action it takes has huge consequences, and because the many many stakeholders involved have diverting, often diametrically opposing interests.
Does that sound like something that Donald Trump, given what we know of him, would be any any way minimally competent at doing?
Of course not. So, although we must keep pointing out that this man is a dangerous xenophobe whose contribution to the national debate has been almost entirely defined by being spectacularly wrong (ahem: remember that Trump got into politics in the first place to demand the President's birth certificate - because he never met a loopy conspiracy theory he didn't like) it's also worth noting that he transparently has none of the minimal qualifications of the job. Including, apparently, even a basic understanding of how it works.