Morning Digest: The front line of the House battlefield is right here

_{The Morning Digest is compiled by David Nir, Jeff Singer, and Stephen Wolf, with additional contributions from the Daily Kos Elections team.}

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Leading Off

● House: Now that the deadline to run for office as a major-party candidate has passed in every state, we have a good opportunity to assess the state of the House playing field nationwide using Daily Kos Elections' calculations of the 2020 presidential election results for the districts in use this fall.

The presidential result is a critical indicator of a district's potential competitiveness because American voters have become heavily polarized by party and are much less likely to split their tickets than in past decades. Because of these tendencies, House results have become tightly correlated with presidential results to a historic degree.

However, that correlation isn't ironclad, and candidates from both parties still regularly win at least some districts that voted for the other party's presidential ticket. Yet, because of presidential headwinds, these "crossover" districts are frequently among the most heavily contested nationwide, and that trend is likely to continue this cycle.

While Joe Biden is no longer the Democrats' standard-bearer, Vice President Kamala Harris is likely to assemble a relatively similar electoral coalition, just as Biden's map was similar to Hillary Clinton's four years earlier.