Chicago Mayor Rahm Emanuel is doing something very uncharacteristic to save his flailing re-election campaign: He’s being nice.

Mr. Emanuel, his acerbic personality muted by a pullover sweater, cut a 30-second ad this week in which he notes that he might “rub people the wrong way,” but that his no-nonsense attitude allows him to make the tough decisions necessary to clean up our fair city. He has a point: It takes a special breed of person to preside over a town whose top exports are, currently, terrifying stories of citywide violence and President Barack Obama .

The mayor might have turned on his charm too late, however. Mr. Emanuel is the first incumbent mayor to face a runoff election since the system was introduced 20 years ago. Chicago has a habit of electing its leaders for life, and few expected Mr. Emanuel to be an exception. But having failed to win a majority in the Feb. 22 election, the mayor will now face Jesus “Chuy” Garcia —a county commissioner, former alderman and former state senator—in an April 7 runoff. This is no pro forma challenge. A poll this week shows Mr. Garcia within single digits of the mayor. “Rahm could actually lose” ran a March 4 headline in Politico.

As far as success stories go, Mr. Emanuel’s could be better. One reason he is having such a hard time is that he has failed to inspire Chicagoans’ true belief. People like Mr. Emanuel, or at least they tolerate him. They might even be willing to forgive his plan to install speed cameras citywide—getting a ticket is known as “getting Rahmed”—if he can lower the rates on parking meters and snag Mr. Obama’s presidential library. But no one really loves Mr. Emanuel.

The opposition’s choice, Mr. Garcia, is a self-proclaimed progressive unmoored from the city’s Democratic machine but backed by powerful teachers unions. When Mr. Emanuel came into office, Chicago faced a $587 million budget deficit. The city’s contract negotiations with public-school teachers, who demanded a 30 percent pay increase and more money for failing schools, hit the skids, and Chicago Teachers Union President Karen Lewis led teachers in a citywide strike.

It ended with a compromise: Teachers received a 17.6 percent pay increase over four years and the promise that any teachers laid off would jump to the front of the line for new openings. Mr. Emanuel got a longer school day and tougher teacher evaluations. But the damage was already done, and the two factions have been at odds ever since.

The teachers unions are among the challenger’s main bankrollers, contributing roughly half of the estimated $1.5 million he has raised. Mr. Garcia has also tied his campaign to a plan that would take the power to appoint Chicago’s school board out of the hands of the mayor; those positions would be elected instead. This would allow the union to use its considerable largess to back school-board candidates sympathetic to its aims. The hilarious twist here is that Mr. Emanuel spent a lifetime burnishing liberal credentials, but has now acquired a Scott Walker-esque reputation for union busting.

Part of the mayor’s troubles stem from the dissatisfaction of progressives, who expected a better deal from President Obama’s former chief of staff. Before the first votes were even cast, MoveOn.org had lent Mr. Garcia its Chicago email list. Democracy for America, a group founded by former Democratic presidential candidate Howard Dean, is also sending emails for Mr. Garcia. The Progressive Change Campaign Committee is raising money under the headline “Defeat Corporate Democrat Rahm Emanuel.” It seems as if every teachers union in the country is focusing off-year election efforts on Chicago to teach Mr. Emanuel a lesson.

President Obama might be getting the message. Though the president cut an 11th-hour ad for Mr. Emanuel before the initial election and made appearances across Chicago, the White House has nothing on the schedule for the runoff. The president remains popular enough in the right areas—among limousine liberals along the Lake Michigan waterfront and African-American voters—that his initial endorsement will have a long tail. But it won’t put Mr. Emanuel over the top. Even the promised presidential library rings hollow with voters who backed Mr. Garcia on the south and west sides. They want a trauma center, not a tourist attraction.

Chicago voters are left to pick between two unappealing candidates who are battling for the measly one-third of the electorate that hasn’t checked out completely. (Voter turnout in the first round was 34 percent). On one hand, there’s Mr. Emanuel, who admittedly inherited a financial mess created from the second Richard Daley to hold the mayoral title, but who seems as hapless now as the day he took control. On the other hand, there’s Mr. Garcia, a man who has many progressive dreams and no idea how to pay for them, and whose best quality is simply that he isn’t Rahm Emanuel.

Local Republicans—the few of us willing to admit our party affiliation in public—couldn’t script a more depressing outlook if they tried. In a city that is perilously close to bankruptcy, besieged by waves of violence and facing an uncertain future, the two factions fight it out over whether pension contracts should be extraordinarily generous or simply generous.

What will happen in the April runoff is anyone’s guess. The lesson for Chicago residents like me is that maybe it is time to move somewhere else.

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