Politicians on both sides of the aisle like to hold up charter schools — publicly funded, privately run schools — as one of the most effective and innovative solutions to a flawed education system. But John Oliver says the American public needs to study up on how well those schools work in practice. 

While charter schools are operating in 42 states, as well as in Washington D.C., there is very little oversight of who is allowed to open a charter school or how well those schools are functioning. On HBO's "Last Week Tonight" Sunday, Oliver broke down some of the more glaring flaws in letting unchecked charter schools take responsibility for kids' educations. 

"It's back to school season, and for millions the school they'll be attending will be a charter school — the thing that politicians love to praise," Oliver said. "Now for this piece — and I know this is going to make some people on both sides very angry — we're going to set aside whether charter schools are a good idea in principle, because whether they are or not, in 42 states and D.C., we're doing them. So instead, we're going to look at how they operate in practice."

The comedian highlighted rampant problems in charter schools across the U.S., including failing schools closing with no notice in the middle of the school year, corrupt school officials pocketing taxpayer funds, a lack of oversight of who gets approved to run charter schools and lax standards for education in operating charter schools. Oliver argued that, when dealing with education, the stakes are too high to allow such malpractice. He took particular issue with a quote from Ohio Gov. John Kasich comparing allowing charter schools to compete against public schools with competing neighborhood "pizza shops" — Ohio has approved more charter schools than most states and boasts one of the highest failure rates

"The problem with letting the free market decide when it comes to kids is that kids change faster than the market," Oliver said. "And by the time it's obvious a school is failing, futures may have been ruined. So if we are going to treat charter schools like 'pizza shops,' we should monitor them at least as well as we do pizzerias. It's like the old saying, give a kid a [bad] pizza, it could [mess up] their day, treat a kid like a [bad] pizza it could [mess up] their life." 

While Oliver admitted that many charter schools in the U.S. have been successful, he says results are uneven from state to state and regulations are lax. The comedian suggested doing some research before trusting a particular charter school with your children.