Democratic presidential hopefuls, including Vermont Sen. Bernie Sanders, Massachusetts Sen. Elizabeth Warren, and Joe Biden, rushed last week to endorse another Chicago Teachers Union strike. They did so just weeks after the union drew criticism for its pledge of “solidarity” with Venezuelan dictator Nicolás Maduro.

Not long after, Chicago teachers walked out on students and families in an attempt to put the screws to Chicago’s freshman mayor, Lori Lightfoot. The Oct. 17 walkout marks the Chicago Teachers Union’s third strike in seven years.