I decided to calculate the congressional apportionment based on 2020 population estimates, both with and without undocumented immigrants:
With undocumented immigrants:Alabama -1Arizona +1California 0
Colorado +1Florida +1Illinois -1
Michigan -1
Minnesota -1Montana 0
New York -1North Carolina +1
Oregon +1Pennsylvania -1
Rhode Island -1Texas +3West Virginia -1Solid Red States (AL, TX, WV): +1
Swing States (CO, FL, MI, NC, PA, AZ): +2
Lean Blue States (MN): -1
Solid Blue States (IL, NY, OR, RI): -2
Obama 2012 states: -3
Clinton 2016 states: -2
Freiwal: -4
Without undocumented immigrants:Alabama 0 (+1)
Arizona 0 (-1)
California -1 (-1)Colorado +1
Florida +1
Illinois -1
Michigan -1
Minnesota -1
Montana +1 (+1)New York -1
North Carolina +1
Oregon +1
Pennsylvania -1
Rhode Island -1
Texas +2 (-1)
West Virginia 0 (+1)Solid Red States (TX, MT): +3
Swing States (CO, FL, MI, NC, PA, AZ): +1
Lean Blue States (MN): -1
Solid Blue States (IL, NY, OR, RI, CA): -3
Obama 2012 states: -4
Clinton 2016 states: -3
Freiwal: -5
#Analysis:If the Trump administration gets its way in suppressing the count of undocumented immigrants, the net effect would be to bank 2 extra EVs for Republicans and take 1 EV away from Democrats, putting 1 more into the tossup category. The easiest electoral path for Democrats (of the current decade) would lose a single EV. This doesn't change electoral math that much, but a map like the one below would be a Dem win with undocumented immigrants counted, and a 269-269 tie without:
Nevada/Iowa AND New Hampshire become critical here.
If Arizona moves left of Wisconsin (and it should), that would provide more paths to victory, but if Arizona fails to pick up a seat due to an undercount, the Dems are hurt even more. A map such as this:
Would also go from 270 for the Democrats to a 269-269 tie.
Sources:
http://www.pewhispanic.org/interactives/unauthorized-immigrants/https://demographics.coopercenter.org/national-population-projectionshttps://www.psc.isr.umich.edu/dis/census/tools/apportionment/