So the scenario I put forth is not meant to be realistic, it's supposed to represent a logical extreme within the system. I'm well aware that assumption 1 is not actually true, as Montana, which has one congressional district, has almost twice the population of Wyoming, which also has one congressional district. As far as Texas being blue, I was just choosing the largest states for the democratic candidate, not necessarily states they would realistically win. The assumptions I chose were because I needed some ground rules in calculating the smallest percentage a candidate in a three-way race could win with, otherwise I could say something completely ridiculous like only one person bothered to vote in California. The way I made my calculation was as follows. I assumed the third-party candidate won one congressional district by one vote in the twenty least populous states. As there are seven states that only have one congressional district, the third-party would control seven U.S. house state delegations. I also assumed the Democrats controlled the 24 most populous U.S. house state delegations (if you're wondering how they can control the 24 most populous state delegations, but not actually hold all of those states on my electoral college map, the answer is gerrymandering). The next six most populous state delegations would be controlled by the Republicans. The remaining 13 state delegations would have split control (no one party controlling a majority of its seats). Since the third-party would control seven delegations, and the Republicans would control six, they would throw their weight behind the third-party candidate. Including DC, there are 436 congressional districts in the country of which the third party would have won 20 of them by a single vote over the other two candidates. 100/436*20/3 = 1.53%