Population shifts are poised to have a tangible impact in 2020, increasing the importance of states in the South and West. | Michelle R. Smith/AP Photo 2020 elections Population boom could remake 2020 map Growth surge ripples across key presidential states.

MIAMI — A handful of presidential battleground states experienced a population explosion over the past year, altering the landscape in at least three key states that stand to play a pivotal role in the 2020 election.

Those population shifts are poised to have a tangible impact in 2020 — with demographic shifts cementing Florida’s premier swing-state status, vaulting Arizona onto the list of 2020 swing states and perhaps putting Nevada further out of reach for President Donald Trump’s reelection campaign.


Both the year-over-year changes and the longer-term trends this decade point to a transformed electoral map in 2020 — shaped both by population shifts and the Trump-enhanced realignment that has come to define modern politics. The population shifts could have even more material impacts after 2020, when the decennial reapportionment process will remake the House of Representatives in 2022 and the Electoral College for the 2024 presidential election.

New Census Bureau estimates released Wednesday of the fastest-growing states between 2017 and 2018 report Nevada is roughly tied for first for the greatest population growth by percentage over the past year (with Idaho, at 2.1 percent). But right behind were Arizona — where Democrats won a Senate election last month for the first time since 1988 — at 1.7 percent, and Florida, which is already the nation’s largest swing state and grew at a 1.5-percent clip over the past year.

While Florida was fifth in growth rate, more U.S. residents moved there than to any other state over the past year. It has the third-highest population of 21 million, the second-highest number of total new residents and 132,000 residents who came from elsewhere in the country.

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Put it all together and Florida is a political powder keg heading into 2020, according to outgoing state GOP chairman Blaise Ingoglia.

“More people means more campaigning, more money, more advertising, more of everything,” Ingoglia, a state representative, said.

The numbers — especially the net domestic migration data — could also mean more pressure for Democrats, who saw their hopes of saving Sen. Bill Nelson and winning the governor’s mansion for the first time in 20 years dashed by historic turnout for Republicans that was likely fueled by a wave of retirees from the Midwest and parts of the Northeast.

“The more older, whiter voters who move here from higher-tax, higher-regulation states, the more we win,” Ingoglia said.

The new census data released Wednesday don’t show the race, age and home state of the new U.S. residents picked up by Florida last year, but they do show that New York lost the most residents (48,510) and Illinois the second-highest number (45,116) between July 1, 2017, and July 1, 2018.

Puerto Rico continued to hemorrhage people, losing nearly 130,000 people, or 3.9 percent of its population.

“Puerto Rico has seen a steady decline in population over the last decade,” Sandra Johnson, demographer and statistician for the Census Bureau, said in a written statement. “Hurricane Maria in September of 2017 further impacted that loss, both before and during the recovery period.”

A disproportionate number of hurricane evacuees moved to Florida from the island, and Democrats hoped they would be a crucial component in fueling a blue wave. But Puerto Rican turnout appeared to lag behind the statewide average — and Republicans ultimately lost only one of five statewide races, for agriculture commissioner.

“The big issue is they left the island, and they came here — but they either didn’t register to vote or not enough of them voted,” said Matt Isbell, a Florida Democratic data analyst.

“We’ve been getting a ton of migration from the Midwest especially, and a lot of them fit the profile of Republican voters,” Isbell said. “And it’s balancing out the growth with Democrats.”

Though demoralized by the statewide losses last year, Democrats have more hope in Florida for 2020. Democratic voters in the state tend to show in greater force in presidential elections — although 2016 was an exception — and this year Democrats came closer than ever before in statewide midterm elections; three of the races for state office were so close they went to recounts. Democrats also picked up a net of two congressional seats, five state House seats and one state Senate seat.

Population growth and demographic change has also roiled the existing political landscape in the West. In Arizona, Democrat Kyrsten Sinema notched the party’s first Senate victory in three decades, and Democrats will actually control a narrow majority of the state’s House seats — five out of nine — in the new Congress. And Democrats are already on a winning streak in Nevada, where changing demographics have propelled the party to victories that include three consecutive presidential elections, two straight Senate races, three out of four congressional seats and unified control of state government starting in 2019.

In Texas, where Democrat Beto O’Rourke came up short in his bid to unseat GOP Sen. Ted Cruz, the closeness of the race reflected both O’Rourke’s strong campaign, and the population growth in the state. In many of the state’s most competitive House races — Democrats picked up two seats in Texas last month — excitement around O’Rourke and Democrats, along with the population boom, led to roughly the same number of votes cast in the midterms as in the 2016 presidential election.

Florida is currently the largest Electoral College prize seriously contested by the two parties, 29 electoral votes, trailing only California (55 electoral votes) and Texas (38 electoral votes). And while those Electoral College numbers are fixed through the 2020 election, Florida is poised to become even more influential in the next decade.

According to a POLITICO analysis, Florida would pick up an additional House district if the end-of-decade reapportionment were conducted today, the new Census Bureau data suggest. But, if the current trends hold for the next two years, Florida could end up adding two seats instead of one, bringing it to 29 House districts beginning in 2022 — and 31 electoral votes starting in 2024.

The states that would gain House seats if reapportionment were held today are all in the South and West: Arizona, Colorado, Florida, North Carolina, Oregon and Texas, which would gain two seats. (Texas could end up with three more seats if it keeps growing rapidly over the next two years.) And the states that would lose seats — Illinois, Michigan, Minnesota, New York, Pennsylvania, Rhode Island and West Virginia — form an almost-contiguous band that stretches from the Northeast through the Midwest.

Other states on the cusp of losing a House seat (and thus a vote in the Electoral College) in the next decade, if the current trends continue: California, Ohio and Alabama. If California loses a House seat — for the first time ever — it would signal the end to an era of almost meteoric growth, particularly in light of the continued, national migration to the Sun Belt.

Shepard and Bland reported from Arlington, Va.