Electoral Map Strategy:  The Road to 270

This article describes how the Road to 270 combinations calculator works.  This feature is found below the 2020 interactive electoral mapIn the discussion below, the term "location(s)" encompasses the 50 states, Washington D.C, and the individual districts in Maine and Nebraska.

Overview: This tool works in connection with the interactive map above it. Based on the remaining undecided locations, it will calculate the paths to 270 electoral votes for both parties, as well as the number of possible 269-269 ties. Each time you modify a location's rating on the map, the number of combinations will update. 

How the Paths (Winning Combinations) are Determined: The calculator assumes that the undecided locations are resolved, in order, from most to fewest electoral votes. Furthermore, only the combinations needed to cross the 270 winning threshold are shown. For example, let's assume locations A, B, & C are undecided and a party can reach 270 by winning A and B. In this case, it is also true that they will add on to their total by winning location C. However, since winning location C doesn't affect the outcome one way or the other, only A & B is considered a winning combination, not A, B & C. 

Limitation: The calculator is active when 12 or fewer locations are undecided. 

Results: The table below the map shows the following for the Democratic and Republican parties:

  • Electoral Votes: These will match the total in the interactive map above it.
  • Needed for 270: The difference between 270 and Electoral Votes (or zero if greater than 270).
  • Winning Combinations: The number of paths to victory (or to a 269-269 tie)
  • Must Win: A party must win this location to have a mathematical chance to reach 270 electoral votes. A must win location will appear in every winning combination.
  • Not Needed: This location is not in any of the paths to 270 electoral votes.  Put another way, winning or losing it will not change the number of winning combinations. However, that doesn't mean the location should be ignored, as winning it may reduce the number of ways the other party can get to 270 electoral votes.

The results area also shows either the number of possible tie combinations or 3rd party electoral votes. 

Results (Ties): If neither party reaches 270 electoral votes, the election is decided in the U.S. House of Representatives. Ignoring faithless electors or other odd situations, in a map where all electoral votes go red or blue, a 269-269 tie is the only case where neither party reaches 270.  If no 3rd party electoral votes are awarded in your map, the number of possible tie combinations will be displayed.

Results (3rd Party): While a 3rd party hasn't won the popular vote in a location since 1968, the interactive map allows you to game out that possibility.  A 269-269 outcome is not possible if electoral votes are won by a 3rd party. However, those 3rd party electoral votes may impact the number of major party combinations, possibly leading to other scenarios where neither party gets 270 electoral votes. If 3rd party electoral votes are awarded in your map, that number is shown here.  3rd party combinations to 270 are not calculated at this time.

Combination Details Page

While the content described above will display the number of combinations available, this is the place to go if you want to see the details of each one. Select the view all combinations link in the Road to 270 area. Landing on the page, you'll see a thumbnail image of your map, as well as icons for the locations you've left undecided. There are options to view the individual Democratic, Republican and tie combinations.

The icons are interactive, allowing you to immediately see the impact of further changes (i.e., assigning additional locations to a party) without returning to the map page.