He did not say that. The quote in question, frequently and incorrectly cited by Harris and her supporters, was directly in response to a question about what he would do if violent riots broke out in the aftermath of the election/inauguration. He stated that he would call in the National Guard and maybe the military. You know, like Pelosi should have done on January 6th, but decided not to. There is video (which Harris conveniently never showed anywhere). Go watch it. This is right up there with the "fine people on both sides" lie. And the "he wants to execute Liz Cheney" lie. The Harris campaign and the media kept repeating these things over and over and it didn't work. I'd like to think it's because the people saw through it. I'm not sure that's the reason, but I'm an optimist. Sometimes.
And the misleading information wasn't limited to Trump, either. She kept stating that she was going to "crack down" on "corporate price gouging." Even answered that this was her plan when asked directly during an interview about how she planned to reduce the cost of living. The problems with this were that she tied this to the cost of groceries, an industry with a very, very low profit margin, and as stated directly in her plan, was limited to emergency situations. But she kept putting it out there as though it was an overall strategy. The woman couldn't answer a straight question with a straight answer.
I think the Harris campaign would have been better served by laying out (reachable) goals and legitimate plans for her vision of the country rather than misleading, lie-laden attacks on Trump. To my eye, it came across as desperate and ill-conceived. Someone also needed to tell her to speak more off the cuff and not just spout the same (Dreams, Ambitions, and Aspirations...) talking points verbatim over and over. It made her seem like she had no plan at all and didn't really know what she was doing. As though she was in way over her head.