Mayors across the U.S. are vowing to push forward with their priorities in spite of the federal government, whether it’s upholding the U.S.’s promise to lower greenhouse gas emissions or defending the legality of “sanctuary city” policies. But their ambitions keep running up against that age-old barrier: funding.

That challenge is only further exacerbated by proposed federal budget cuts that would slash national housing, transportation, and social programs that cities rely on.

That’s why Michael Bloomberg’s announcement of a $200 million investment into American cities over the next three years is, for the most part, welcome news. Announced Monday at the U.S. Conference of Mayors, the Bloomberg Philanthropies’ new American Cities Initiative will kick off with this year’s Mayors Challenge, which invites every city to propose solutions to some of today’s most prominent urban issues—that includes anything from climate change to gun violence to the opioid crisis.

And the stakes are even higher than before. Cities have until August 18 to sign up for the challenge, and the first 300 to do so will have the opportunity to sit down with the foundation’s innovation experts for a “day of ideas generation,” according to James Anderson, Bloomberg Philanthropies’ head of government innovation programs. From there, 35 “champion cities” with the boldest ideas will get up to $100,000 to experiment, and the eventual winner will receive $5 million dollars for implementation. Four runners-up will each get $1 million.

But the higher stakes mean the judges are looking for cities to tackle large-scale issues with bold ideas that can help move not just one city, but the entire nation, forward. One main criteria is how well the idea can be applied from one city to the next. Essentially, “can this idea spread?” says Anderson. “If it works, can it be transferred to other cities, do other cities face that same challenge, and would they likely adopt the solution?” (This, in fact, has been the mantra for many of Bloomberg Philanthropies’ other initiatives, including its Innovation Teams program that’s focused on technology.)

As the New York Times reported, this challenge is former mayor Michael Bloomberg’s latest “anti-Washington” move against the Trump administration and the overall inefficiency of national policymakers from both parties. Cities, Bloomberg told the Times, will have to “replace Washington and, in some cases, state governments, to provide services.” And it’s up to the mayors to work together in absence of a federal framework.

Yet Henry Grabar at Slate makes a key point about Bloomberg’s latest pledge:

The grand prize is small potatoes relative to billion-dollar big-city budgets, and the entire dedication of $200 million is pocket change against the billions the Trump budget cuts from the transit grants, housing voucher programs, and other federal outlays on which cities depend.

Just take a look at Trump’s proposal to eliminate the Community Development Block Grant program as part of his plan to downsize the Department of Housing and Urban Development. The move would devastate the popular Meals on Wheels program that feeds millions of seniors and people with disabilities—undeniably a pressing urban issue—which alone will cost cities $3 billion.

So how can cities use Bloomberg’s charity to even begin making a dent on the national scale? Anderson, echoing another Bloomberg Philanthropies mantra, says it’s starts with giving cities leeway to experiment with new and sometimes risky ideas—even if they’re on a small scale.

“We're trying to get cities to stick their necks out, to innovate and think big,” he says. “In cases where those ideas catch hold, we want to put wind behind them and help them scale across the country.”

Andersen points to the astonishing boom of bike-share programs in the U.S. It essentially began in 2010 with some four systems and 320,000 rides across a few cities, according to the National Association of City Transportation Officials. By 2016, there were 55 systems and 28 million rides—and its popularity is only growing. “Other cities notice, and it caught on, and collectively they're having quite a significant impact on the national level,” he says. “That's the idea behind the competition.”