in 2016: democrats won 53% of the vote, republicans 43%
in 2014: democrats won 43% of the vote, republicans 52%
in 2012: democrats won 53% of the vote, republicans 43%
Part of the problem when comparing popular votes nationally is that you often have situations in CA where the two candidates running for office in the general election are both democrats. when the sum total of those votes is 10m, or the differential between the number of votes the republicans received nationally and the number democrats received nationally, is it fair to complain about a lack of representation? Other times within house races there wont even be a challenger.
Saying "it's not democratic!" isn't a useful comment.
We know.
One downside to strictly proportional representation is that a concentrated majority can make decisions without collaborating/cooperating with the minority.
Example: Coastal states with large populations could just ignore the other states with small populations.
The US bicameral congress balances the proportional House against the non-proportional Senate.