How bad is the census news for Democrats?

The first numbers from the nation’s decennial census were published this week. On top of providing top-level figures about the U.S. population — which grew to 331,449,281 last year — census data is used to determine how many seats in the House of Representatives and how many Electoral College votes each state gets.

The total number of House seats is capped at 435, meaning for one state to gain a seat, another state must lose one. Texas added 4 million new residents in the past 10 years and is the...