Well, let's see.
According to the NYT/Siena polls, a slight majority of Americans think Trump would do better on foreign policy than Biden.
Trump - who has indicated he'll pull the US out of NATO and cut off support for Ukraine - which is to say, he'll cede all of central Europe back to Russia.
Trump - who will happily support a murderous Saudi Arabian regime in places like Yemen.
Trump - who will happily endorse the worst elements in Israel, who will look the other way (or look for a place to build a golf course!) as Israel continues to appropriate West Bank land from its occupants.
The polls say a majority think Trump would do better on the economy than Biden. Which is to say, spiteful tariffs are somehow economically beneficial. Which is to say union-busting is good economic policy. Etc.
A majority say Trump would do better on immigration than Biden. Which is to say open discrimination against brown people is good. Which is to say family separation (destruction) is good policy. Which is to say that nativist hate is good policy.
Do you really want to argue that people who either believe these things, or else are oblivious to Trump's intended policies (and track record) are sharp-witted?
When I say that lots of Americans are too ignorant to see through the obvious disinformation pumped out by Fox, Newsmax, etc.... I mean just that.
Now, ignorant is not the same as stupid. Stupid implies a cognitive limitation. Ignorant implies either laziness, or else a willful refusal to learn. Lots of Americans who aren't "stupid" are in fact breathtakingly ignorant - because they, for whatever reason, have not made the effort to be honestly informed, or because they've been deliberately misled by people who have a selfish interest in exploiting them, in pursuit of wealth or power.
Donald Trump is certifiable. Listen to, or read what he actually says. Don't dismiss it as "Trump being Trump." He means it. He is not sane. This is obvious, if you pay attention.
But a lot of Americans do not pay attention. They follow false media, and don't think for themselves about national or international issues. That is ignorant. (Not necessarily stupid.)
Then there's a much smaller number of Americans who absolutely know better, but who are sufficiently selfish and greedy that they'll happily exploit this ignorance, in pursuit of personal benefits. These are the people who actually work to keep the ignorant people in the dark.