Political Fallacy?

It is not really a logical fallacy but merely speculation based on a subjective opinion. 

It becomes fallacious because of the expressed certainty. 

E.g. "I think things could have been different if Trump was in charge" vs "If Trump were in charge, this wouldn't have happened!" 

Dr Bo's answer is spot on.

I am politically neutral for the most part. I vote in every election but am in no way partisan toward a specific party. But I feel this is a broad assumption that if Trump was still in office this would not have happened. I believe in empiricism and that if he isn’t the president we don’t know exactly what would of happened or how he could of handled it. Just like we wouldn’t of known exactly how Biden would have handled the challenges from 2017-2021 during Trumps presidency because he wasn’t in office.

Sounds a lot like a Single Cause/Oversimplification Fallacy...

Bo, This fallacy confuses me a little.

To my mind a situation where the evidence clearly contradicts the speculation is a different situation from mere hypothetical speculation which we cannot know the truth about.

If we say, "John can't be at home because his car isn't in the driveway," and yet he is because, unusually, his car just happens to be somewhere else strikes me as a different kind of speculation from "John and Mary wouldn't have split up if she hadn't had an affair." Maybe they would have regardless, we can't know.

To my mind a situation where the evidence clearly contradicts the speculation is a different situation from mere hypothetical speculation which we cannot know the truth about. 

In either case, the speculation is unsupported. Stating "as fact" (or with unwarranted confidence) is the fallacious part. This is different than saying something like "if I went to class today I wouldn't have missed my exam."

[To Bo Bennett, PhD]

Thanks, Bo. I still find the two cases different.

The first is clear contradiction of the facts - John is home.

The second is purely in the realm of the hypothetical. We cannot know whether they would have split up anyway but there is no actual contradiction of facts involved. There is simply no contradiction of facts in asserting that John and Mary would have split up if she hadn't had an affair so to call it an example of "hypothesis contrary to fact" is not accurate in my opinion. It is purely in the realm of the hypothetical in my opinion.

 The fallacy entails treating future hypothetical situations as if they are fact. This is where the "contrary to fact" comes in. Something that might have happened is not a fact.

As usual, I don't care if someone doesn't think a named fallacy is a good fit—all informal fallacies are arguments in themselves and are open for debate. What I care about is that people realize when something is unreasonable. If you know John and John said, "Dude, I am telling you with 100% certainty, the only reason I am splitting up with Mary is because she had an affair. There is no other reason," then clearly this is in a different category than pure speculation. Language should be adjusted to match the probability of the event about which is being spoken. Failing to do so is being inaccurate and possibly deceptive. Failing to understand that people have strong biases and are mostly ignorant to this rule of communication, and taking statements such as "John and Mary wouldn't have split up if she hadn't had an affair" at face value, (i.e., assuming factual without evidence like the person explaining what John told them), is a problem with reasoning, thus fallacious.

[To Bo Bennett, PhD]

Thanks for your patience, Bo. I get it now. I was confusing "contrary to" with "contradicting". "Contrary to fact" simply means "not being a fact" rather than contradicting a fact. I'm glad I cleared that up because it bugged me, I always felt strange naming a speculation as that fallacy when it didn't feel quite right. Now it does.

[To Bo Bennett, PhD]

Just to clarify, Bo: I accept they're both fallacious and they're both stating something "as fact" when neither is a fact, however, to me they're still significantly different because:
--- one is a clear contradiction of fact

--- one can only ever be in the realm of the hypothetical.

It is simply wrong to say that the statement, "John and Mary wouldn't have split up if she hadn't had an affair" is "Hypothesis contrary to fact", it's simply speculation. There is no fact that it's contradicting. We simply can't be sure what would have happened if she hadn't had an affair because the fact is she did. I'd feel much happier if there were two separate fallacies here:

one which relates to contradiction of fact

one which is purely in the realm of the hypothetical and cannot be proved

What evidence?  There is no evidence of what would have happened if Trump were President.  This is purely speculation and hypothetical so I agree with Dr. Bo that this would be hypothesis contrary to fact .  

But my example was John and Mary splitting up because she had an affair. People often say an affair split a couple up so it's not unreasonable to speculate that John and Mary wouldn't have split up if she hadn't had an affair, however, it's simply something we cannot know, they might have split up anyway. We simply cannot know if they would or wouldn't have split up if she hadn't had an affair. It's just speculation. In the case of John speculating that John wasn't home, however, it is absolutely contrary to fact. He is home.

To me these scenarios different:
One is speculation where we cannot know the answer, it is purely in the hypothetical.
One is speculation which is clearly wrong.