The Iran-Contra scandal from the Reagan administration comes to mind. Congress explicitly de-authorized the executive from funding the Contras in Nicaragua. The executive kept doing it anyway. Nobody faced any consequences, though Congress at least made a lot of noise about it.

That's kind of ineffective, but not to this level where Congress is just fine with blatant illegality.

The Department of Defense is so named by legislation. Executive orders cannot override legislation.

It might surprise some people that courts are wise to this sort of thing. Lawmakers generally empower them to ignore such legal fictions.

I don't remember people thinking HW Bush was dumb. Or McCain, or Romney, or Ryan, or McConnell, or even someone like Gingrich. Quayle, Palin, W Bush (very incorrectly, dude was wrong and/or lying about a lot of stuff but he wasn't dumb), and Trump, sure.

The thing those people have in common is that they have unorthodox public speaking styles. Especially Trump. It's kind of a pro wrestling adjacent style -- lots of performative bombast, specific tropes referencing cultural touchstones, I'm not trying to change anyone's mind on any substantive issue. I'm just trying to put myself into a particular box in the viewer's mind. It can be effective, but when it's not, it comes off as buffoonish.