By projecting these recent trends forward, we can forecast what the electoral map will look like after 2020.4 As the table below shows, many of the states that will probably lose an electoral vote are in the Northeast and Rust Belt. Rhode Island, New York, Pennsylvania, Ohio, Illinois and Michigan are all likely to lose a vote. Minnesota, West Virginia and Alabama will also likely lose one. Those electoral votes will all go to states in the South or West. Texas is on track to gain three, Florida two, and Arizona, Colorado, North Carolina, and Oregon one each. (These projections are similar to those from the Election Data Service, a political consulting firm that released its own estimates in December.)

These estimates could still change, although with only four years left until the 2020 census, the major trends are probably mostly baked-in. Still, unforeseen shifts are possible. The best recent example of that happened in 2005, when Hurricane Katrina hit the Gulf Coast, causing Louisiana’s population to shrink by a quarter million people. The state’s population eventually rebounded, but the storm may still have cost the state a congressional seat (and electoral vote) in the 2010 census. (Many Louisiana residents displaced by Katrina settled in Texas, which may have contributed to Texas gaining four seats, rather than three, after the 2010 census.) Less dramatic, but still significant, were the shifts during the housing boom and bust of the 2000s: Before the 2008 recession, some of the country’s fastest-growing states (such as Nevada, Arizona and Georgia) were adding population at a rates at or above 2 percent per year. During and after the recession, growth rates in many of those states dropped to around 1 percent for several years. Struggles in the fossil-fuel industry have also substantially slowed or reversed population growth in a handful of states (Alaska, North Dakota, West Virginia and Wyoming) in recent years.