How we cite our quotes: (Essay.Paragraph)
Quote #4
A common passion or interest will, in almost every case, be felt by a majority of the whole; a communication and concert result from the form of government itself; and there is nothing to check the inducements to sacrifice the weaker party or an obnoxious individual. (10.13)
This is pretty much the definition of what we know as mob mentality. Take Shays' rebellion for example: It was a case where a majority—the farmers—decided to take up arms to put down a minority group—the wealthy merchants who were squeezing them for money they didn't have.
Madison's idea of a minority group just might not be the same as our idea of a minority group in politics, at least in terms of power-to-population ratios. A billionaire is in a much, much stronger position of power than a hundred people making minimum wage, for example.
Quote #5
It can be little doubted that if the State of Rhode Island was separated from the Confederacy and left to itself, the insecurity of rights under the popular form of government within such narrow limits would be displayed by such reiterated oppressions of factious majorities that some power altogether independent of the people would soon be called for by the voice of the very factions whose misrule had proved the necessity of it. (51.9)
It's interesting that Madison used Rhode Island as his example, considering the Rhode Island state legislature was one of the first to vote against the Constitution. Was he tossing what he viewed as some well-deserved shade?