Mayor-elect Zohran Mamdani is framing his visit on Friday with President Trump as an “opportunity,” adding: “I will work with anyone to make this city more affordable.” If he’s true to his word, mightn’t the mayor-to-be want to take a page from Mr. Trump’s playbook on, say, the merits of lower taxes for New Yorkers, or the need for fewer regulations on city businesses? A thriving economy, after all, is the best way to bolster affordability for all New Yorkers.

Mr. Trump, moreover, is an expert on affordability. Hence the tax cuts that were the signature legislative achievement of his first term, and extending the reductions that has been an early landmark of his second. The economic advantages are undeniable. Yet New York City — along with the rest of the Empire State — stifles its own affordability by overtaxing its residents. The state ranks 50th in America in the Tax Foundation’s State Tax Competitiveness Index. 

A nonpartisan watchdog group, the Citizens Budget Commission, laments that “New York State and its localities already have the highest taxes and the second-highest spending per capita in the nation.” Far from suggesting any tax relief for city residents, Mr. Mamdani campaigned on a pledge to raise levies, especially on wealthy residents of the city — at least those who haven’t yet decamped for Florida or other more affordable states.

The Budget Commission warns that this high-tax regime has  limited prospects, warning that “New York’s relative attractiveness to residents and businesses is threatened by flexibility in a changing economy,” or, in other words, the fact that New Yorkers can pull up stakes if they want to keep more of their own income. The commission adds that “affordability challenges” as well as “concerns about public service quality and safety” threaten an exodus.

New York’s income and property taxes are bad enough for individual residents. Yet Mr. Mamdani has his eye on a tax hike for businesses, too. So cautions the Manhattan Institute’s E.J. McMahon. Currently New York state’s top corporate tax rate is 7.25 percent. That rate is the 17th-highest in America among states that levy a corporate tax — Ohio, Texas, and Nevada are among those that lack such a levy on businesses. 

In a campaign pledge that garnered less attention on the hustings, Mr. Mamdani is proposing to boost the top tax rate to 11.5 percent, matching the level set by New Jersey, which is now the highest in America, Mr. McMahon reports. Yet considering the surcharge levied by the Metropolitan Transportation Authority in the region,  Mr. McMahon adds, “Mr. Mamdani’s proposal would take this up to 13.7 percent, easily topping all states.” Meaning, unaffordable.

“If it works for our regional neighbor, why can’t it work for us,” Mr. Mamdani asks of his proposed tax jump. Yet if the new mayor’s goal is to foster more growth, higher employment, and increased wages among New Yorkers — the most direct paths to achieve greater affordability — higher taxes on the city’s private businesses are hardly the logical approach. Hence the logic of Mr. Trump’s cut in the federal tax rate on corporations.

Mr. Trump has also made slashing red tape a priority of both his terms in the White House, vowing to cut 10 regulations for every new one issued. Mr. Mamdani has so far shown little appetite for loosening the fetters that crimp free enterprise in the city, though. Instead the new mayor is aiming, say, to impose costly new rules on  greenhouse emissions and interfering in businesses’ hiring decisions. These moves will make New York City less, not more, affordable.