If you’ve ever run a long-distance race, you know that the beginning is quite thrilling. There’s the crack of the starter pistol, the runners’ gradual but dramatic surge forward, the cheers of the crowds lined up along the first half-mile or so. But soon thereafter the crowd thins and the noises die down. As the pack separates and spreads out, even the sound of other competitors fades away, and you’re more or less alone with your footsteps and your thoughts. Your only rival is the timers’ clock. The key thing becomes concentration.

Four months ago The Nation and City Limits launched this blog to track Bill de Blasio’s transition and his first 100 days in office—the sprinting start of an administration critically important to the progressive movement and to a city we love that has seen an alarming increase in social inequality.

Those first 100 days have come and gone, and as I note in today’s Nation article, de Blasio has managed to, on one hand, deliver on an admirable list of campaign promises while, on the other, encountering challenges that make it painfully clear how hard it will be for him to make good on his larger vow to create a more just city. Some of those challenges—the slowness of his appointments, the mishandling of the press—are of his making. Others, like the subservience of the city to Albany’s whims and Governor Cuomo’s drive toward the center on economic policy, are not.

But now that UPK is in the state budget, the stop-and-frisk suit has moved toward settlement, paid sick-leave is law and other early targets have been tackled, de Blasio is in that long middle phase of the race, when the cheering has died down and the initial rush of adrenaline gives way to whatever strength and stamina he brought in. De Blasio is not a new mayor anymore. Now—more so than he already has through snowstorms and building explosions—he’ll have to weave his progressive vision into the daily fabric of managing the city.

This blog will end, but both The Nation and City Limits will keep watching—with hope in our hearts, not cheering so much as shouting out reminders that the clock is ticking.