Celebrating his victory in the Democratic primary in September, Mayor Bill de Blasio — apparently quoting famed Spanish artist Pablo Picasso — exulted, “Everything you can imagine is real!” It’s one thing for a surrealist to proclaim limitless, fantastic possibility as part of his artistic manifesto, but it is less intriguing, and less comforting, to hear it from a municipal official whose job is to propose budgets, manage the city’s finances and govern a complex bureaucratic infrastructure.

Looking ahead to Mayor de Blasio’s virtually assured second term, it is instructive to examine the way he has operated up to now and consider how his record will mesh with his pledges, which have been intentionally vague and surprisingly light. De Blasio’s major campaign promise seems to be “more of the same.” So what should we expect?

The mayor’s major accomplishments in his first term include universal pre-K, a reduction in the number of traffic deaths and the continued decline in the city’s crime rate. UPK, and the plan to expand all-day preschool to 3-year-olds, is a popular program because it essentially serves as a form of publicly funded day care, relieving families of a significant expense.

The early socialization of 3- and 4-year-olds will probably make their transition to kindergarten easier, but decades of research and experience — Head Start has served tens of millions of kids since 1965 — have generally determined that early childhood education does not significantly impact later educational outcomes: Most gains disappear by third grade.

So while UPK and U3K are effective subsidized child-care programs, they are unlikely to deliver the profound socially transformative changes that Mayor de Blasio has promised.

Vision Zero has cut vehicular deaths through a combination of lower speed limits, stricter enforcement and traffic-calming measures. Every avoided pedestrian fatality is to be celebrated. But the mayor has otherwise not done a good job managing the streets, which are now experiencing the worst congestion in history.

Crosstown Manhattan taxi speeds average six miles an hour, and it is now often quicker to walk. Expansion of Select Bus Service is salutary, but the mayor adamantly refuses to consider congestion pricing below 60th Street or tolling the East River bridges to generate revenue to improve mass transit.

The mayor loves to call New York the safest big city in America, but Gotham had that status before he was on the scene. Our enjoyment of low crime rates today is the fruit of decades of dedicated Broken Windows policing and the implementation of CompStat, the scientific, data-driven system that targets crime hot spots before they erupt and spill over into adjoining neighborhoods. The revolution in policing that has saved thousands of lives and transformed our city has had profound effects that cannot be rolled back overnight. However, de Blasio’s steady decriminalization of quality-of-life and “minor” crimes has already led to a degradation of street life that is palpably apparent to everyone. New York City is still safe — for now — but who knows how long we will remain immune to the increase in violent crime that is affecting every other big city in the country.

The mayor’s other big ideas are too vaguely defined even to be measured by the time he leaves office in 2021

The mayor’s other big ideas are too vaguely defined even to be measured by the time he leaves office in 2021. His plan to “build or preserve” 200,000 units of affordable housing depends on increasingly creative definitions of “preservation” and “affordability.” Refinancing the privately-owned but subsidized Mitchell-Lama units is great for their residents, just as rent freezes for stabilized renters make them happy, but it does nothing to ensure long-term availability of new units for young New Yorkers moving out of their parents’ houses or for newcomers to the city. New York has by far the largest system of public and subsidized housing in the nation, yet we still have a massive housing crunch. At what point will the city wake up and realize that only the market will provide the quantities of housing we need and open up existing stock for every income level?

Mayor de Blasio has announced that he wants to close the Rikers Island jail complex within 10 years (halfway into his successor’s second term) and replace it with local borough jails. He says that his plan requires New York City to reduce its average daily jail population from approximately 10,000 to 5,000. The city has already reduced bail requirements and bends over backwards to divert miscreants into jail alternatives; contrary to myth, Rikers is not filled with honors students who were caught puffing a joint or pocketing a candy bar. So it is unclear how this major initiative will occur.

Similarly, the mayor has plans to replace the existing homeless shelter system with 90 new shelters to keep homeless people close to their communities. Neighborhood opposition to this plan is fierce, but in any case, the plan does not address the huge increase in the unsheltered homeless population that has occurred in the last few years. The mayor has finally acknowledged that the problem of street homelessness is real, and that 6,000 people — a 39 percent increase under Mayor de Blasio — are sleeping rough in New York City every night, and the city has no plan for how to deal with them.

Mayor de Blasio has been extremely lucky in his first term, because a surging stock market has kept the city’s coffers flush with tax revenue. Unlike virtually every other municipal executive in the nation, the mayor has never really had to formulate a budget, in the sense of cutting back in one area to fund others. He has been able to say Yes to everyone and everything. Free school lunch for all? Sure. Give tens of millions of dollars to private school-bus companies every year in order to supplement their drivers’ pay? Absolutely. Promise to buy back the CHARAS/El Bohio building in the East Village for 10 times what the city sold it for? Why not!

As long as the economy stays strong, Mayor de Blasio can make sunny promises about everything imaginable being real. But what will happen, as it surely must, when the economy slows down and the tax revenue dries up? That’s when we will really be able to take the measure of our mayor.

Seth Barron is associate editor of City Journal.