> was sworn to the bar without actually going to any sort of law school.
It can still be done today in most US states.
Also, note that even the self-represented can take on a government and win. See Jim Pattison's (Canadian billionaire) tax hearings vs. the Crown (Canada), which he won after a decade of litigation. Multiple prosecutors and judges retired during that time period.
Besides developing further tax filing methods for his empire, you can bet he wasn't sued again by the government - they hate taking a loss. (The US SEC infamously tries to undermine defendants today by going after their ability to pay lawyers before trials.)