Our project to calculate the 2020 presidential results for all 435 congressional districts nationwide hits Arizona, which gave its electoral votes to Democrats for only the second time in more than 70 years. You can find our complete data set here, which we're updating continuously as the precinct-level election returns we need for our calculations become available.
Joe Biden defeated Donald Trump in Arizona by a close 49.4-49.1 four years after the state backed Trump 49-45, a result that made Biden the first Democrat to take its electoral votes since Bill Clinton in 1996. Before that, the last Democrat to carry the state was Harry Truman in 1948.
Biden managed to win five of the Grand Canyon State’s congressional districts, which was one more than Clinton, while the remaining four went for Trump again; all the Biden seats are represented by Democrats, while the Trump seats remained in Republican hands. Biden also improved on Clinton’s margin of victory everywhere except the 3rd and 7th Districts, which are the most Democratic seats in the state. You can find a larger version of our map here.
We’ll start with a look at the 1st District, which is the only district that went from Trump in 2016 to Biden this year. This sprawling constituency in the northeastern part of the state had supported Mitt Romney 50-48 before going for Trump by an even narrower 48-47, but Biden took it 50-48 this time. Democratic Rep. Tom O'Halleran, who had previously served in the legislature as a moderate Republican, won a third term 52-48 against Republican Tiffany Shedd in a race that attracted millions in spending from outside groups on both sides.
Biden also made big gains in two seats that were competitive just a few years ago but have quickly veered away from the GOP. The 2nd District in the eastern Tucson area had backed Romney 50-48 before going for Clinton 50-44. The seat continued to move left this time by supporting Biden 55-44, and Democratic Rep. Ann Kirkpatrick prevailed by a similar 55-45 margin.
The shift over the past decade was even more dramatic in Democratic Rep. Greg Stanton’s 9th District, which is home to central Phoenix and eastern suburbs. The seat supported Obama 51-47 in 2012 before going for Clinton by a wide 55-38 margin. Biden took it by an even larger 61-37, which makes this his biggest improvement over Clinton’s margin in any of the state’s nine districts.
Biden performed best in the 3rd and 7th Districts, but as we noted above, his margin of victory was smaller than Clinton’s four years ago even though he took a larger percentage of the vote (and more raw votes). Rep. Raul Grijalva’s 3rd District, which stretches from the Yuma area west to Tucson, moved from 62-33 Clinton to 63-36 Biden.
Rep. Ruben Gallego’s Phoenix-based 7th District went from 72-23 Clinton to 74-25 Biden, which represented a 0.17% drift to the right. Both seats are heavily Latino, a demographic that in many places moved toward Trump, though the shifts were considerably smaller here than they were in several comparable seats in neighboring California.
We’ll turn now to the four Trump seats. National Democrats made a strong effort to unseat scandal-ridden Republican Rep. David Schweikert in the 6th District, a once safely red seat in Scottsdale and North Phoenix that had moved from 60-39 Romney to 52-42 Trump. Trump’s margin of victory this time shrunk to 51-47, but that was enough to carry Schweikert to a 52-48 victory over Democrat Hiral Tipirneni.
Trump decisively carried the remaining three districts, but Biden made gains in each. Trump’s margin of victory in Rep. Andy Biggs’ 5th District in the Phoenix suburbs of Mesa and Gilbert shrunk from 58-37 to 56-42, his second-largest decline in the state after the 9th. The shift was only a little smaller in another suburban Phoenix seat, Rep. Debbie Lesko’s 8th District, where Trump's margin sank from 58-37 to 57-41.
Rep. Paul Gosar’s giant 4th District in the north-central part of the state, meanwhile, was again Trump’s best seat in the state by far, though Biden still trended up a bit here: While Trump won 68-28 here in 2016, he carried the seat 68-31 this time.
Arizona’s congressional and legislative maps are drawn by a bipartisan commission, but Republicans have done everything they can to eliminate it. In 2015, the Supreme Court upheld the body’s constitutionality by just a 5-4 margin, and since then, the court has moved to the right. If the commission is struck down, the Republican-controlled state government would control the mapmaking process.