It's by disseminating power that we best insulate ourselves from policies damaging to society at large.
Pithy riposte: how did that work out for people of African origin in the USA for several centuries?
It's an easy one to point to, but there's no shortage of examples from every corner of the planet. Majorities don't typically give a damn about minorities. Democracies go a step further and sanctify the majority - but it's democratic!