The union shunned 5-year, 24 percent teacher raises and continues to demand more, including thousands in new hires and additional benefits like affordable housing.

Over 25,000 teachers and 7,000 support staff will be on strike while 300,000 students will be left in the lurch. 

It's become standard operating procedure for the CTU to strike when it doesn't like the school district's contract proposals. In 2012, the union struck for one week over a contract dispute with then-Mayor Rahm Emanuel. It did the same again in 2016, when the union held a one-day walkout. 

In both cases, the union's demands drove Chicago deeper into its financial hole. Now this strike poses a new danger to the fiscal viability of the city and the school district. The simple fact is that Chicagoans can't afford either the CTU's demands or Lightfoot's offer.

Regardless of how the strike ends, the massive costs inflicted on CPS will force Chicagoans' tax bills to keep rising, the city's population to keep shrinking and property values will continue to suffer. Neither side's deal will help teachers or residents if the city and the school district move faster toward insolvency.