Sure, the 'oppressed' founding fathers were more worried about the common man being oppressed than having their 'perfect union' go down in history as a failure.
Put yourself in their shoes. Governments are getting overthrown all over the place. You are a rich landowner who just created a new government which might not be overwhelmingly popular with the masses. I know! Let's give them all guns.
Some of them might have thought so but the clause 'a well regulated militia' got thrown in there as a safety mechanism. Sorry but that is just the way it went down.
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Well Regulated
The Random House College Dictionary (1980) gives four definitions for the word "regulate," which were all in use during the Colonial period and one more definition dating from 1690 (Oxford English Dictionary, 2nd Edition, 1989). They are:
1) To control or direct by a rule, principle, method, etc.
2) To adjust to some standard or requirement as for amount, degree, etc.
3) To adjust so as to ensure accuracy of operation.
4) To put in good order.
[obsolete sense]
b. Of troops: Properly disciplined. Obs. rare-1.
1690 Lond. Gaz. No. 2568/3 We hear likewise that the French are in a great Allarm in Dauphine and Bresse, not having at present 1500 Men of regulated Troops on that side.
We can begin to deduce what well-regulated meant from Alexander Hamilton's words in Federalist Paper No. 29:
The project of disciplining all the militia of the United States is as futile as it would be injurious if it were capable of being carried into execution. A tolerable expertness in military movements is a business that requires time and practice. It is not a day, nor a week nor even a month, that will suffice for the attainment of it. To oblige the great body of the yeomanry and of the other classes of the citizens to be under arms for the purpose of going through military exercises and evolutions, as often as might be necessary to acquire the degree of perfection which would entitle them to the character of a well regulated militia, would be a real grievance to the people and a serious public inconvenience and loss.
--- The Federalist Papers, No. 29.
Hamilton indicates a well-regulated militia is a state of preparedness obtained after rigorous and persistent training. Note the use of 'disciplining' which indicates discipline could be synonymous with well-trained.
[Excerpt]
Read more:
Meaning of the words in the Second Amendment