Coalesce and Oppress
In the 10th Federalist Paper, James Madison throws down some solid arguments in favor of an "extensive republic" as opposed to a democracy. Let's dissect the differences between a republic and a democracy. For starters, in a republic, there is a delegation of the government to a smaller number of citizens elected by the rest. Another advantageous trait of a republic is its sheer magnitude. While this may initially seem to be a downfall, it actually makes it more difficult for a majority to coalesce and oppress the feeble voice of the minority(s). In other words, an extensive republic doesn't allow for a tyranny of the majority. In short, a republic controls and even limits the effects of factions better than a democracy.