This week’s election will likely mark another milestone in the partitioning of America into divergent and increasingly hostile blocs of red and blue states.

From New Jersey and Virginia to California, Tuesday’s results are poised to extend a process that has allowed each party to consolidate political control over a huge swath of the country and that is heightening conflict among the states to a degree unmatched since the civil rights era in the 1960s — if not, the Civil War a century before that.

This week’s voting could further this separation in two distinct ways. Democratic victories in the governor’s races in Virginia and New Jersey would continue the trend of Democrats winning most elected offices in the states that typically go blue in presidential elections — while the inverse is increasingly true for Republicans in typically red states.

Even more important, though, this week’s vote will almost certainly accelerate the redistricting war that threatens to uproot one of the last beachheads for both parties in the geographic area dominated by the other. Following moves by Texas and other Republican-controlled states to eliminate Democratic House seats, the near-certain passage of Proposition 50 in California to erase up to five GOP-held seats will escalate the redistricting arms race between the parties. As that struggle unfolds across the country, it is likely to doom a substantial share of the remaining House members from each party in states that usually vote the other way for president.

As it becomes more difficult for each party to compete for nearly any office in the other side’s strongholds, both may grow increasingly inclined to write off the interests and perspectives of the places outside of their coalitions.

President Donald Trump has raised this dynamic to an ominous height by treating blue states less as partners in governing a federal republic than as hostile territory to be subdued. But even future presidents less inclined than Trump to view regions that voted against them as “the enemy within” may find it growingly difficult to craft national policies acceptable to both sides of this hardening red and blue divide.

Whether it’s Trump’s