In close elections, Republicans are favored to win even when they lose the popular vote.

By Ian Millhiser @ Vox.com, Sept. 17

Clearer than ever that the "if we would just GOTV" mantra is hogwash as far as the presidency (and the Senate, for that matter) is concerned. To win, it's a necessity to convince some crucial swings to vote for you. It's built-in:

[....] To reach their conclusions, the research team ran hundreds of thousands of simulated elections under various election models. The paper as a whole studies three periods in American history: the Antebellum period from 1836 to 1852, the Reconstruction period from 1872 to 1888, and the modern period from 1964 to 2016 (although many of their modern samples only look at the period from 1988 to 2016). These periods were selected to exclude eras when one party typically won in a landslide.

Overall, they conclude that “the high probability of inversion at narrow vote margins is an across-history property of the Electoral College system.” The Electoral College has, at various times, given an advantage to Democrats, Republicans, and the now-defunct Whig Party. Now it gives a clear advantage to Republicans.

The Electoral College skews elections by giving a structural advantage to small states. Each state receives a number of electoral votes equal to the number of United States House of Representatives members from that state, plus two. These two additional votes effectively triple the voting power of the smallest states, while having only a negligible impact on the voting power of large states.

Additionally, modern-day Democrats are disadvantaged because they “have tended to win large states by large margins and lose them by small margins.” [....]