evidence: We can see just how large this advantage was if we average the margins in the two "tipping-point" states of Pennsylvania and Wisconsin, or the states that delivered (or would have delivered) the decisive 270th electoral vote Biden and Trump needed to win, respectively. (Biden’s tipping-point state was Wisconsin, while Trump’s would have been Pennsylvania, provided he also won Georgia, Arizona and Wisconsin.1) Averaged together, their margin was about D+0.9 points, or roughly 3.5 points more Republican-leaning than the national popular vote margin. This is significant because, as you can see in the chart below, the last time a party had an advantage this large — or larger — in the Electoral College was in 1948, when the GOP’s edge was 3.8 points. [...] Ultimately, it’s impossible to say where things will go from here — we don’t know who’ll be running in 2024 or what the conditions will be. But if the Frost Belt states such as Michigan, Pennsylvania and Wisconsin continue to lean somewhat to the right of the country, that will benefit the GOP in the Electoral College — unless there is a counter-shift elsewhere in the Democrats’ favor. In 2020, for example, Biden narrowly carried traditionally Republican states like Arizona and Georgia. Those two states alone can’t make up for Democrats losing that Frost Belt trio, but Democratic improvement in those states and other places in the Sun Belt (whither "Blue Texas?") could undo the Republicans’ current edge in the Electoral College.