Well, it depends on how one interprets those events and then whether they are honestly presented to support one's arguments, doesn't it?
You frame Ho Chi Minh as one worthy of U.S. support in the 50's, and that to withhold such support was "one of many mistakes made by the U.S."
I haven't thought about him in recent decades but a quick glance reminds he was educated as a young man in the USSR during the 1920's and was sponsored-employed by its Comintern (which, when under Lenin, was just as ruthless as ever). He was always a dedicated communist and always disposed of his political enemies quite ruthlessly.
Are you surprised the U.S. ignored his overtures in the mid 40's given what it knew about him and after witnessing the USSR's behavior in the same time period?
Finally, the Dem-led Congress in the 70's wasn't just "power-drunk" as you suggest, they were also leftists; see for instance, the history of Kamla Harris and Dem Congressman "Red" Dellums.
Have a nice day.