Rahm Emanuel, who was easily elected mayor of Chicago in 2011, now faces a runoff election on April 7 against Jesus G. Garcia.

The surprising setback for Mr. Emanuel has ignited a debate here -- and in Washington -- about what happened in the lead up to the Feb. 24 election, and what comes next.

How did President Obama’s former chief of staff fail to get the majority he needed after winning handily four years ago? Which issues are motivating voters and why?

The New York Times asked readers from Chicago to share their experiences living in the city during Mr. Emanuel’s tenure. The responses (more than 1,000 and counting) do not amount to a scientific survey; rather, they are a sampling of engaged opinion.

Not surprisingly, readers mainly focused on schools -- outlining what they loved and hated about one of Mr. Emanuel’s defining acts, overseeing the decision to close nearly 50 public schools deemed underperforming, underutilized or both.

Many said they were teachers who were outraged at the mayor's approach to education, which also included tougher teacher evaluations and an expansion of privately run, publicly funded charter schools.

But many readers, including lifelong Chicagoans and millennials who are newer arrivals, also highlighted other issues that led them to criticize or praise the mayor, from his handling of city finances to plowing snowy streets.

Here is a look at the issues that are at the forefront of readers’ minds, organized by overall theme.