Donald Trump is fond of saying the voting in the US is rigged. For fun, let’s look at the polling for a generic race in the House. Pollsters’ compilation of the polls has a generic Democrat getting 45.9% and a generic Republican with 42.5% (9.7% are undecided and 1.9% are for others). This, of course, means that Republicans are expected to hold the House:
Note that because of partisan gerrymandering and other factors, Democrats would have to win the popular vote by a substantial margin to take control of the House of Representatives. For example, the national House popular vote in 2012 (blue line) gave a margin of 1.2% for Democrats, yet Republicans currently control the chamber, 234-201.
Now that’s rigging the vote–more people voted for Democrats and yet more Republicans were elected. The trouble for Trump is that this kind of rigging doesn’t work for Presidential elections, that’s why Republicans push so much to make it more difficult for likely Democrats to vote.