Bernie SandersBernie SandersSanders sings Obama's praises for stopping Dakota pipeline Feds deny permit for Dakota Access pipeline Of principle and compromise: A paradox within America’s political discourse MORE got his biggest cheer of Sunday night’s presidential debate in Flint, Mich., when he suggested the Republican debates were the result of rampant mental health problems.

“We are, if elected president, going to invest a lot of money into mental health,” Sanders told the Democratic debate audience. 

“And when you watch these Republican debates, you know why we need to invest in mental health.”

The audience cheered loudly at the line, and Sanders’s rival on stage, Hillary ClintonHillary Rodham ClintonArmed man arrested at DC pizzeria targeted by conspiracy theory Clinton opponents vow to continue their pursuit ExxonMobil CEO, retired admiral will meet with Trump about State: report MORE, laughed loudly.

Clinton gave Sanders the opening for his zinger when she said, “We have our differences, and we get into vigorous debate about issues. But compare the substance of this debate with what you saw on the Republican stage last week.”

Thursday night’s GOP debates included a lot of name-calling and a moment in which front-runner Donald TrumpDonald TrumpWould Aretha Franklin perform at Trump inauguration? ‘Good question.’ Ryan: Dakota pipeline pause is ‘big-government decision-making at its worst’ Ivanka was finalizing Japanese business deal at time of Trump, Abe meeting: report MORE defended the size of his hands.