What happens when Chuy’s glow fades?

Since the Feb. 24 mayoral election, a certain “Chuy” glow seemed to descend on the city.

Chicagoans began to believe Jesus “Chuy” Garcia could actually win this.

He’s the underdog who was never supposed to get this far against Mayor Rahm Emanuel. He was Chicago’s David in the race against Goliath.

He entered the contest just four months before the election. He didn’t have a firm financial plan on hand. He raised only $1.3 million, just a fraction of the $15 million Emanuel raised.

But he survived.

Early last week, polling showed Garcia neck and neck with Emanuel.

Now that we’re nearly inside of four weeks before the April 7 runoff, however, that glow is about to wear off.

We may all be looking at this through a different lens: Garcia was never supposed to get this far. He just entered the race. He only raised a fraction of what Emanuel could raise.

Will he survive?

If he wants to beat Emanuel, there’s a few things he needs to do off the bat:

• Offer up details on how he will tackle the city’s roughly $20 billion pension hole.

• Give real details on a repeated promise that he’ll put 1,000 more police officers on the street.

• Address fiscal issues with real details that add up.

• Perform at three upcoming debates; demonstrate he can go toe-to-toe with Emanuel.

• Stay on the offensive, i.e., bring up Gov. Bruce Rauner and Emanuel’s longstanding friendship with the Republican multimillionaire as much as possible.

• Draw broader financial support from smaller donors — and not just labor.

For the last week, Garcia has succeeded at staying on the offensive. He’s grabbed headlines while ripping on Emanuel, including suggesting Emanuel and Rauner should discuss the budget over a pricey bottle of wine. Drawing a line connecting Rauner and Emanuel can only help Garcia at this point, given Rauner’s proposed budget that would slash city services. Given the amount of labor support behind him, Garcia being elected as Chicago’s next mayor would almost certainly be a nightmare scenario for Rauner, who unions say has a “political obsession” with waging war on them.

Emanuel knows the danger he’s facing in this runoff. He wasn’t a national Democratic strategist for nothing. Expect him to do far more than put on a V-neck sweater and give voters a pseudo-apology as he did in a new TV ad.

From now until Election Day, Emanuel will pummel Garcia with attacks that the Cook County commissioner is unprepared for the city’s top job and that he lacks the financial know-how to tackle the city’s $20 billion unfunded pension debt.

Experts have said repeatedly that either a tax hike will soon be in order or city services must be cut drastically to manage the pension pressures. Both Emanuel and Garcia will face pressures to specify how they plan to meet a state-mandated, $550 million payment due in December to shore up police and fire pension funds.

Garcia has said he would lay out more specific plans this week. For his part, Emanuel has been open to raising property taxes in the past, but his supporters argue that Emanuel has shown he’s a tough negotiator with unions, asking them to share in some of the costs.

Emanuel’s campaign is likely to attempt to portray Garcia as opening the city’s treasury to the unions who have funded his campaign.

They portray Garcia as promising the world without explaining how he’s going to pay for it.

“At this rate, Chuy’s next campaign promise will be a ‘unicorn in every pot,’ ” Emanuel campaign spokesman Steve Mayberry told the Sun-Times. “With Chicago at a critical juncture, the city can’t risk having a mayor who makes expensive promises with no way to pay for them.”

Last week, Garcia said he would take down red-light cameras if elected. While the move has populist appeal, it raised questions over how he would fill that $70 million annual revenue gap.

Garcia didn’t say how the revenue could be replaced.

But he’s promising budget details this week.

Depending on how that unfolds, Chuy’s glow could radiate for some time. Or fade fast.