Louis, when you say that the 2nd amendment isn't incorporated, did you mean it was not ratified by every state? This is news to me, if true. I thought that the entire constitution had been ratified by all the states that then existed. Please educate me on this.
On the intent of the writers, I think it is pretty clear that one reason, in addition to defending against invasion, that the citizenry should be armed, was so we could rise up and overthrow the government if it were to become tyrannical. When our petitions to the government for redress of grievances are met with inaction or retaliation, for example. Like when peaceful protesters are attacked or arrested, or when they are herded into what I call "free speech cages" made of highway barricades. That, by the way is what Tampa is planning to do to the protesters who attend the RNC convention. That is what the police in D.C set up for the counter demonstrators at the Reason Rally.
Free speech cages... yep, that's the only kind of free speech we know in Canada. And even those aren't 100% safe.