The DC City Council last week gave final approval to a bill that would force Walmart and other big-box stores to pay workers no less than $12.50 an hour, rather than the city’s current minimum wage of $8.25. Reacting to the hike in pay, Walmart has threatened to scale back or kill six planned stores in DC.

The bill now goes to Mayor Vince Gray. Here’s why he will nix it:

1) Gray personally convinced Walmart to develop stores in the District. The council’s vote amounts to a basic “bait and switch.” Gray lured Walmart to town, helped negotiate land deals, and extracted $3.8 million in charitable gifts. The council’s last-minute salary hike borders on breach of faith. Every year DC politicians take junkets to the International Council of Shopping Centers to attract major retailers. If the council vote sticks, the District has seen the last of big-box, brand-name stores.

2) Gray has promised to create jobs and lower unemployment. He’s been very successful, so far. The District still needs jobs, especially east of the Anacostia River, where Walmart has planned to open stores. Minimum-wage positions are a necessary path into the employment stream for many people, especially the many DC residents who have been out of the workforce for years. The District’s minimum wage is already $1 above the federal level.

3) Gray knows that neighborhoods east of the Anacostia are retail deserts. DC residents are tired of heading east to Prince George’s County to buy basic needs, from clothes and food to appliances and auto parts. They want the inexpensive goods Walmart provides, and as a resident of Hillcrest, the mayor hears these complaints every day.

4) DC needs Walmart more than Walmart needs DC. “We’re at a point where we don’t need retailers,” council member Vincent Orange said. “Retailers need us.” Gray knows Orange has delusions of grandeur. Especially in the District’s eastern wards, retailers have to be convinced to set up shop.

5) Leadership: Walmart building stores east of the Anacostia River is a personal matter for Mayor Gray. The store proposed for the Skyland Shopping Center would make Gray’s neighbors happy. He lives a half mile away, and his friends have complained for years that they need a place to shop for basics. If Gray doesn’t run for reelection, his bringing Walmart to the city will be a foundation of his legacy. If he does enter the race, he can run on bringing jobs and stores east of river. It’s a win-win. On the other hand, if Gray vetoes the bill and can’t get enough votes to fend off a council override, it will be a lose-lose—for Gray and for the city.