Faithless electors will not affect the resolution of this market - resolution will be based on expected/pledged electoral college votes given the popular vote totals and actions of faithless electors will not be considered.
For a Democrat to win 350 EVs, assuming they win every state Biden won in 2020:
Win Texas plus any one of Ohio, North Carolina, or Florida, or Texas plus Iowa plus any other state or district
Win Florida plus Ohio, or Florida plus North Carolina plus any other state or district
Win North Carolina, Ohio, Iowa, ME-02, NE-01, *and* Kansas
For a Republican to win 350 EVs, assuming they win every state Trump won in 2016:
Win Minnesota, Nevada, New Mexico, New Hampshire, NE-02, and all of: ME-AL, Virginia, and Colorado.
Now let's do some math as I show my assumptions here.
If Dems win TX; Dems win one of OH, NC, FL = 100% - [Rs win all three if Dems win TX] (0.75 x 0.3 x 0.6 = 13%) = 87%
If Dems win TX but lose OH, NC, and FL; Dems win IA (50%) plus any other EV (100% - [Rs win all of NE-01, ME-02, KS, AK] (0.75 x 0.6 x 0.8 x 0.6 = 22%) = 78%) = 39% of 12% = 5%
P(D_350 if D_TX) = 92%
If Dems lose TX but win FL; Dems win OH = 25%
If Dems lose TX and OH but win FL; Dems win NC (70%) plus any other EV (100% - [Rs win all of IA, ME-02, NE-01, AK, KS] (0.9 x 0.8 x 0.95 x 0.8 x 0.95 = 52%) = 34% of 75% = 26%
P(D_350 if D_FL and R_TX) = 51%
If Dems lose TX and FL; Dems win 350 EVs = chance Dems win ALL of NC, OH, IA, ME-02, NE-01, KS = 0.35 x 0.2 x 0.15 x 0.2 x 0.05 x 0.1 = 0%
P(D_350 if R_FL and R_TX) = 0%
If Rs win every state Trump won in 2016; Rs win 350 EVs = chance Rs win ALL of MN, NV, NM, NH, NE-02, ME-AL, VA, CO = 0.2 x 0.8 x 0.35 x 0.3 x 0.25 x 0.05 x 0.05 x 0.01 = 0%
P(R_350) = 0%
P(D_TX) = 15%
P(R_TX and D_FL) = 7.5%
P(R_TX and R_FL) = 77.5%
P(D_350) = 0.15(0.92) + 0.075(0.51) + 77.5(0) = 0.176 is roughly 17.5%. P(R_350) = 0.
I feel like this market should be below 20%, and I'm gonna put some mana on it once I have more mana to spend.
https://www.britannica.com/topic/United-States-Presidential-Election-Results-1788863
Last happened in 2008.