"The financial crash? Us. Crack epidemic? Us. Star Wars prequels? You better believe it."
There are seriously Hydra agents everywhere in the Marvel Universe. What happens to American history when it's proven that an offshoot of Nazi Germany has been embedded in every major governmental organization for the last 80 years? Suddenly, no conspiracy theory is too stupid to discredit, no institution above reproach, no living American's faith in the system left even remotely intact.
Was Nixon a highly trained Hydra agent? There are ways it could make sense. Is Donald Trump a trainee Hydra agent, bumbling through a plan he found in Red Skull's notes? It's the only thing that makes sense. And speaking of Trump, he and every other idiot would accuse their enemies of being Hydra members after any disagreement. ("A lot of smart people are saying this -- tremendous people. You see how she whispers in Obama's ear? You see that?") It'd be like the Red Scare, only if had turned out Joe McCarthy was badly underestimating the conspiracy and/or was totally in on it.
The Red Scare / Red Skull thing is so on the no-- uh, you know what we mean.
Did Hydra have anything to do with the Manhattan Project? Vietnam? The assassinations of JFK and MLK? Every significant American moment would now be suspect. Any history book that didn't blame everything on Hydra would probably only indicate that it was printed by a publisher controlled by Hydra.