Such an idea is so monstrous they can’t wrap their minds around it – add to it that those who support the man are accomplices in that destruction…
One way to at least get them to think about their support of the Destructor is to ask them to pose an alternative reasoning for his actions – they won’t be able to do this.
Thus they won’t admit to you that you’ve made them doubt their allegiance to his hopechangeness, you will have at least made them think on the subject.
Oh, they’d be able to offer an alternative - it would involve something like “I’m sure he intends well, because _I_ intend well, and I support him.”
Of course, that veers into the realm of “incompetence”, and they don’t want to go there either, because that would be racist.
Oh, and another thing I use as an argument:
“So, let’s say Obama isn’t out to destroy the economy and the country - what would he be doing differently if he WERE?”