I rather suspect he does actually know.
I mean, given the controversy, deceit and lies by her husband Bill regarding his sexual infidelities; the way that the Clintons have personally enriched themselves and alleged corruption surrounding large financial donations to the Clinton 'foundation'; the general air of scandal and cloud of suspicion which surrounds and follows the Clintons, is fairly well documented and reported.
So too is the (resumed) investigation in to her somewhat suspect use of a private email server which is being conducted by the FBI.
It's not a good look.
Put simply, she's not trustworthy and everyone knows that.
The difficulty for Archer is that, as someone who has been convicted of perjury, you simply can't go anywhere near a debate about the integrity of someone else.
It would be difficult to acknowledge or accuse someone else of being deceitful or of lying, at any time; let alone on live, national T.V.
Fortunately for him, the absurd pretence that he had no idea why crooked Hillary was so unpopular, was of course unchallenged by the ever sickly-sweet Kay Burley, ever keen to be P.C. who promptly lauded and feted him, as if royalty.