An influx of tens of thousands of Californians to Arizona over the past few years could help Kamala Harris win the Grand Canyon State in November, according to one prominent political scientist.

The most recent U.S. Census data shows over 74,000 Californians moved to Arizona in 2022 alone, a traditionally Republican state which has become a key battleground in recent years.

In 2020 Joe Biden beat Donald Trump in Arizona by less than 11,000 votes, a major win in a state that backed the Republican firebrand over Hillary Rodham Clinton in 2016 and voted against Barack Obama in both the 2012 and 2008 presidential elections.

Arizona has undergone a dramatic political change over the past decade and a half, which has seen Democrats make major inroads in what had been a GOP stronghold. In 2010 the Republicans had both Arizona U.S. Senate seats, a supermajority in both chambers of the Arizona Legislature and controlled every statewide office. By contrast now the governor, secretary of state and attorney general are all Democrats and both of the state’s senators were elected on the Democratic ticket, though Kyrsten Sinema later switched to be an independent.

Sinema isn’t standing for re-election in November and polling gives Democrat Ruben Gallego, currently a House member, a clear lead over Republican Kari Lake in the battle to be her successor.

Speaking to Newsweek Mark Shanahan, an expert in U.S. presidential politics at the University of Surrey in the U.K., said Californian migrants had helped make Arizona competitive for the Democrats.

He said: “The influx of Californians to Arizona isn’t homogenous. They cut across age boundaries from young tech workers through agricultural laborers to retirees. But they are more likely to have a history of voting Democrat, or at least be anti-Trump and willing to be swayed towards Harris over Trump and Gallego over Lake.

“Incomers are less likely to come from rural Republican stock and the net effect is to turn this once ruby red state a much paler shade. Maricopa and Pinal Counties—the most populous in the state—are now seen as far more pro-Democrat while the east and west of the state is staunchly Republican.”

Referring to the 2020 presidential election Shanahan added: “The problem for Republicans is that most of those moving from California head to the Phoenix and Tuscon areas and they are swaying the voting balance. Relatively few thousand new Democrat votes could make all the difference is a very tightly contested race.”

However, Dafydd Townley, who teaches American politics at the University of Portsmouth, said the Arizona presidential battle is unlikely to be “decided” by Californian migrants and instead pointed to abortion as a potentially decisive issue.

He said: “As in previous polls, Arizona will be a key state in the election. There is an assumption that those migrating to Arizona will be Democrats, however, California does have pockets of strong Republican voters that might be included in those leaving the Golden State. It’s unlikely that the electoral votes for Arizona will be decided on this one factor.

“Reproductive rights are expected to be a key feature of the campaign in Arizona when voters will decide whether to protect abortion rights within the State Constitution. Whether those 74,000 former Californians will be decisive in enshrining those rights will only be revealed in November.”

Newsweek contacted representatives of the 2024 Kamala Harris and Donald Trump presidential election campaigns for comment via email.

An AARP poll of 600 likely Arizona voters released on Tuesday put Trump ahead of Harris by two points, with the backing of 49 percent of respondents versus 47 percent for the current vice president. The poll was conducted between September 24 and October 1 with a four-point margin of error.