Good question.
Right now, Putin’s mental state matters more, because he controls nukes and can start wars, while Trump no longer does and his aggression is stymied by Twitter. So, this question is more of a mind exercise than anything.
I vote for Trump. That he’s unhinged, I mean.
Everyone recognizes Putin is more emotional these days. Sen. Chuck Grassley (R-IA) admits Putin’s state of mind is discussed in closed Senate briefings, and Sen. Marco Rubio (R-FL) said “it’s pretty obvious something is off” with him. But veteran U.S. intelligence analyst Beth Sanner (profile here) argues he isn’t “insane or unhinged … I don’t think he’s crazy,” but only “highly emotional right now.” (See story here.)
Trump, by contrast, is unhinged. Hitting the news today is this: “Former U.S. Attorney General William Barr said then-President Donald Trump became furious after Barr told him there was no evidence that the 2020 election was fraudulent.” Barr described how, as he explained this, “he was obviously getting very angry about this” and then fired him on the spot. (See this story here.)
If Putin is emotional, Trump is more emotional; and if Putin is unhinged, Trump is more unhinged. In my view, it’s no contest, which is more or less a good thing — to the extent it’s possible for anything about this to be good — because, as I said, Putin still has nukes and Trump doesn’t. I mean, bad as things are, it could be worse. On a relative scale of things, you want the guy with nukes to be more in control of himself (hopefully).
But for world-class temper tantrums, neither of them holds a candle to this guy; thank God he never got nukes (and didn’t get close, see article here).