Leftist comedian Bill Maher challenged liberals over the weekend on his HBO show "Real Time with Bill Maher" on a key 2020 issue: free college.

Unlike many in his party, though, Maher challenged the conventional thinking of "free college," pointing out that it would only hurt the poor.

"are we really saying that someone who didn't go to college should be subsidizing the people who went and got the benefit?"

Maher's comment came just days after 2020 Democrat presidential candidate Sen. Elizabeth Warren outlined her plan to offer "free" four-year college through raising some taxes. At least two more Democrat 2020 presidential candidates, Sen. Kamala Harris of California and Sen. Bernie Sanders of Vermont, have also indicated they support the idea of "free" four-year college.

Warren, Sanders, Harris, and 2020 Democrat presidential candidate Sen. Amy Klobuchar of Minnesota support "free" two-year college for all. Rep. Alexandria Ocasio-Cortez (D-N.Y.), who is not yet old enough to run for president but introduced the Green New Deal, also is an outspoken supporter of "free" college for all.

[RELATED: FREE, FREE, FREE: 2020 Dems dish up higher ed policies]

Despite multiple presidential candidates in his party supporting "free" college, Maher took a step back, pointing out that "nothing is free."

"If you have a Bachelor degree, you earn on average 65 percent more than someone who doesn't have one. If you have a Master's degree, 100 percent more over the course of your lifetime. So nothing is free. Like a free lunch? No. Neither is college," Maher said. "Somebody will be paying for this free college and it will be taxpayers, so are we really saying that someone who didn't go to college should be subsidizing the people who went and got the benefit from going to college and made more money?"

Maher's guest, conservative Grover Norquist, agreed, adding, "that's an incredible transfer from lower-income people to higher income people. If you look at the beneficiaries of that proposal, it is a huge subsidy to higher income people and if you're out buying votes, you go with the people you think are going to vote."

Watch the clip by clicking here.

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