The American electoral system was set up so that voters could choose their representatives, but in reality, politicians get to choose their voters thanks to gerrymandering - the redrawing of electoral districts to favor one political party over the other.

"Gerrymandering is partly responsible for giving Republicans such an edge in the House of Representatives," John Oliver revealed on the latest episode of Last Week Tonight.

"Whoever draws the districts has a lot of power," he added. "And thanks to technological advances, it's possible to use that power in very precise ways...gerrymandering has become a very precise science. And interestingly, it's one of the few remaining types of science in which the Republican currently believe."

Unfortunately, we can't combat gerrymandering by simply telling politicians that they can't redraw electoral districts. Those lines are revised from time to time for good reason.

"There is nothing inherently wrong with redrawing a voting district. It's actually necessary. They need to have around the same number of people in them and populations shift over time as people move or die," Oliver explained. "And that is why, every 10 years, we have a census. After which, lines are redrawn for both the U.S. House and state legislatures."

So the problem isn't the process itself but the people charged with carrying it out. "[I]n most states, the lines are drawn by politicians," Oliver said. "In fact, in 37 states, the drawing of state legislative districts is primarily controlled by the legislators themselves. And they have a pretty clear vested interest there."

And they aren't technically doing anything wrong. Rejigging electoral districts for political gain might be unethical, but it isn't illegal, according to Oliver.

"If you are thinking, 'Shouldn't all of this be illegal?' Well, that's complicated. Because if you're gerrymandering to disadvantage minorities - yes, that is illegal under the Voting Rights Act. But if you're gerrymandering to disadvantage members of an opposing party, that has generally been allowed. So, racial gerrymanding - no. Partisan gerrymandering - that's kind of okay."

For now, at least. There is a push to take redistricting away from politicians and allow independent commissions to revise electoral maps instead. And Oliver is joining the cause - along with a juggalo, a middle-aged quidditch player, your racist grandmother and others in a coalition of misfits who want their voices to be heard - even if they have nothing intelligent to say and make awful life choices.