Because the progressive/liberal agenda has worked out so well for America's big cities:
NEW YORK — Bill de Blasio overwhelmingly was elected mayor Tuesday, becoming the first Democrat to lead New York in 20 years and ushering in an era of activist liberal governance in the nation’s largest city.
[. . .]
De Blasio’s administration will be a laboratory of sorts for modern progressivism — testing whether an anti-establishment activist can effectively manage a sprawling municipal government and lessen growing inequality between the rich and poor.
Wonder which will happen first, bankruptcy or criminal thugs flooding gack into the streets? Hope he doesn't go too far with that activism. Before you know it, New Yorkers would be told what they can eat and drink. Oh, wait.