One of the historical factoids that puzzles me is why the Congress failed after the 1920 census to follow Article I, section 2 of the Constitution requiring a decennial reapportionment of the House of Representatives. As a result, no changes were made after the 1910 census until 1932.
The answer, of course, was politics. A few Republican states were big winners under the 1920 census: California would have gained 3 seats, Michigan and Ohio 2 each. The losers would have been several southern states that were reliably Democratic and midwestern farm states that usually voted Republican. But in Congress itself, the body which had to pass a law imposing reapportionment, the impact would have been significant. Eleven states would have lost seats, denying incumbents their seats, so those members had an incentive to delay action.
According to historians, two factors other than party advantages help explain the congressional inaction. One was the wet-dry split. Prohibition was the law of the land after January 16, 1920, but efforts were already under way to reverse that decision -- and the 1920 census would have given more power to areas, including growing cities, that were less enamored of Prohibition. The second division in Congress was between rural and urban constituencies, and growing cities would have gained more power under the 1920 census, as they eventually did under the 1930 census and reapportionment.
Gridlock prevailed on the issue throughout the 1920s, notwithstanding the clear words of the Constitution.