Excessive blinking can indicate anxiety, which often pairs with lying. If the level of blinking seems exaggerated, it might be because the person is lying. Eyes that don't match up with general facial expressions may demonstrate internal conflict or a covering up of the truth.
@SaltyVeruca Maybe he's going into a belated Goth phase?
And JD Vance was doing his smug mugging for the camera whenever Walz was speaking. He's bad at it (Kamala was a pro) and so it came across very heavy handed (er... lidded) with the constant eye flashing .
@Lulz4l1f3 Then there's the smudged eyeliner.