This market exists for two main reasons: I think a cumulative-independent approach is the most useful format for markets like this, and I also wanted a market where people could directly compare their predictions about Harris's bid to other modern presidential election results.
A combination of the Federal Election Commission's numbers and Dave Leip's numbers will be used to resolve this market. Dave Leip's numbers will be used for the 2024 election.
Note that if it gets close, the answers that refer to a specific candidate should be taken as not the exact number listed in the answer, but the actual percentage of the popular vote that the candidate got in that election - e.g. the Joe Biden answer should not be taken as 51.31% exactly, but instead as the percentage of the vote total he actually got according to the FEC (81,283,501/158,429,631=~51.305744%) or according to Dave Leip's numbers for elections that predate the FEC reports.
I've made Dave Leip's numbers the resolution criteria this time, so you won't have to wait for the FEC report. If Dave Leip's website explodes I'll use whatever looks like consensus to me among other election results sources, in the interest of speedy resolution. If there's a big disagreement between reputable sources for specific thresholds, then I'll wait for the FEC report.
Please ask any questions in the comments if you have any.