Someone is really jumping the shark on this one. The census will not be completed in time for the 2020 election. Even if it was the states will need to redraw district lines, (after hearings in the state’s legislatures), to accommodate the additions or subtraction of representatives, which requires the drawing of maps, voting on the maps and then defending the maps in court, (a new requirement these days if the maps are drawn by Republicans).
The earliest the changes will show up in state representation is 2021/22.
“Someone is really jumping the shark on this one.”
BB
How the Political Map Is Likely to Shift After the 2020 Census (7/22/2019)
So we have a pretty clear idea of which states will be winners and losers in congressional reapportionment, based on Census estimates and projections. According to a late-December 2018 analysis from Election Data Services, Texas will pick up three House seats and Florida two; while Arizona, Colorado, Montana, North Carolina, and Oregon will gain one each. New York is projected to lose two seats, while Alabama, Illinois, Michigan, Ohio, Pennsylvania, Rhode Island, and West Virginia are expected to lose one. California and Minnesota are thought to be on the bubble for possibly losing one seat.
So here's the net result if we take these numbers at face value:
2016 "RED" STATES: Texas (+3), Florida (+2), Arizona (+1), Montana (+1), North Carolina (+1), Alabama (-1), Michigan (-1), Ohio (-1), Pennsylvania (-1) and West Virginia (-1) ... total net change +3
2016 "BLUE" STATES: Colorado (+1), Oregon (+1), New York (-2), Illinois (-1) and Rhode Island (-1) ... total net change -3
It's also worth noting that the two states "on the bubble" for potentially losing one seat after the 2020 census are both BLUE states (California and Minnesota).
New York's decline has been astonishing. After the 1930 census New York had 45 House seats. It had 41 seats as recently as 1972 before the post-1970 redistricting was done. If it loses two seats after 2020 it will be down to 25.