[5] Post was once again a candidate for re-election in 1932, but his anti-Tammany stances led to his replacement on the Democratic ballot line,[6] forcing him to run under the Citizens Union ticket.

He came in third place with 24% of the vote, splitting the Democratic vote and leading to the election of future United States Attorney General Herbert Brownell Jr.[3] In the 1933 elections, Post allied with former congressman Fiorello La Guardia, who was running for mayor of New York City, and became the Republican-City Fusion candidate for Manhattan Borough President.

[9] His colleagues were social worker Mary Kingsbury Simkhovitch, housing advocate Louis H. Pink, Jewish Daily Forward general manager Baruch Charney Vladeck, and Catholic priest Edward R. Moore.

[3] Post held the offices of Tenement House Commissioner and NYCHA Chairman until 1937, when friction with mayor La Guardia led him to resign in anger.

[14][15] He moved to the West Coast in 1940 and became regional director of the Federal Public Housing Authority, serving until the agency's dissolution in 1947.