President Trump on Tuesday threatened to take federal action to stop Mamdani’s new pied-à-terre tax, which hits New Yorkers who own a valuable second home. Last month, Mamdani implemented a so-called luxury property tax on second homes valued at $5 million or more. The property tax also affected certain co-ops valued over $1 million. On Monday, a Staten Island Supreme Court Judge temporarily blocked Mamdani’s property tax as the lawsuit makes it way through the legal system. President Trump said he is looking into taking federal action to stop Mamdani’s property tax.