Both parties see Maricopa and its growing Latino population as a crucial prize in the fight for the Senate and the White House

MESA, Ariz.Alex Rosado, wearing a face shield and mask in 100-degree heat, walked door to door among ranch-style houses, talking to voters in a neighborhood that is one of the front lines for political organizing ahead of the November election.
Thirty years ago, nearly 80% of the people who lived in this part of the city were white. Now, more than half of residents on these blocks dotted with palm trees, taquerias and churches identify as Latino, according to Census Bureau estimates.
Whoever wins here in Maricopa County, home to Mesa, Phoenix and more than half of Arizonas residents, is likely to win the stateand potentially determine control of the Senate and whether President Trump or former Vice President Joe Biden win the White House.
Interviews with nearly three dozen voters, activists, politicians and researchers say the election could hinge on turnout among Latinos, who make up about a third of the countys population. Exit polls have shown Latinos generally lean Democratic by about a 2-to-1 margin.
The importance of Latino turnout in this newly competitive county was why in late July, Mr. Rosado, a lead organizer for the Democratic organization CASE Action, was out knocking on doors. His pro-immigrant advocacy group halted in-person organizing earlier this year because of the coronavirus pandemic. But they worried they would lose ground if they tried to only contact people virtually.
The reality is, if we dont have these conversations theyre just not going to vote in November, Mr. Rosado said.
Democratic activists are trying to turn out voters like Hector Nunez and persuade them to vote for Mr. Biden. Mr. Nunez, a 49-year-old Phoenix resident, said that even though the construction industry where he works has been doing well under Mr. Trump, he believes the president is racist. Still, he said he didnt know enough about Mr. Biden to commit to vote for him yet.
I think hes doing a good job in a lot of ways, but I think hes bad for the country in a lot of ways, Mr. Nunez said of Mr. Trump.
While Mr. Biden and the Democratic Party largely halted in-person campaigning over the summer due to the pandemic, Republicans here have been holding events and knocking on doors. A spokesman for Mr. Trumps re-election effort said it has held dozens of Latinos for Trump events in Arizona and has three offices in the state.
Voters need to know they have elected officials who are available to them and not avoiding them, said Tatiana Peña, a Republican candidate for a state House seat in a longtime Democratic stronghold. She approached Mr. Nunez to talk about the election after he and his son finished fishing earlier this summer at a park.
Ms. Peña estimates she does at least three in-person events a week, often with the Trump campaign and Republican Party.
Most polls this summer have shown Mr. Biden with a narrow edge over the president in the state, making Arizona a battleground this year. The state has backed Republicans for president for more than 20 years. But Kyrsten Sinema won the 2018 U.S. Senate race here, the first Democrat to do so since the 1980s, in large part by flipping Maricopa County. The county was solidly Republican less than a decade ago, but has moved toward Democrats in recent elections.
Martha McSally, the Republican who lost in 2018 and then was appointed to Sen. John McCains seat after his death, is up for re-election this year. She is facing Democrat Mark Kelly, a former astronaut, in November. Recent polling has Mr. Kelly ahead. Still, as with Mr. Biden, some Latino voters say they dont know enough or arent excited about Mr. Kelly.
Gabriella Varela, the executive vice president of the Arizona State University Young Democrats, feels like she has to vote for Mr. Biden and Mr. Kelly, but she isnt impressed with either of their campaigns. In March, she was on stage with Vermont Sen. Bernie Sanders during a primary rally.
Activists here began organizing in 2010, when large-scale protests broke out in response to Senate Bill 1070known locally as the Show Me Your Papers lawthat required local law enforcement officers to demand documentation from anyone they believed to be in the country illegally. Later, organizers pivoted to engaging Latinos in hopes of defeating Maricopa County Sheriff Joe Arpaio, an immigration hardliner. He lost re-election in 2016, the same night Mr. Trump was elected.
Mr. Trump won Maricopa County by about 3 percentage points, a narrower margin than the previous two Republican presidential candidates. Ms. Sinema won it in 2018 by about 4 percentage points. She performed well in suburban areas and in majority-Latino areas, where turnout was up nearly 17 percentage points compared to 2014, according to a Wall Street Journal analysis of precinct-level election results and Census Bureau data.
Republicans say midterms are different than presidential elections, when turnout is higher. They are confident that Mr. Trump will win Arizona again and boost Ms. McSally.
The Trump campaign says that the pre-pandemic economy and the GOPs socially conservative policies will help them with Latino voters, 77% of whom say they are Christian, according to Pew Research. The campaign has said its primary focus, though, is getting people who voted for the president in 2016 to do so again. That group, exit polls indicate, leans white, male and older.
Here in Maricopa County, the population has boomed over the past decade, and last fall the county saw unemployment decline to 3.6%its best readings since the 2007-09 recession. But when the pandemic hit, unemployment jumped to 12.5% in April, had a slight recovery in May but then edged back up to 9.7% in June, when the area was hit particularly hard with outbreaks of the virus.
In areas of the county where Latinos make up a majority of the population, Ms. Sinema won in 2018 by a margin of nearly 51 percentage points, according to a Wall Street Journal analysis. That was more than 6 percentage points better than Hillary Clinton performed in those areas in 2016.
A mid-July survey conducted by polling firm Latino Decisions on behalf of the left-leaning advocacy group Unidos US found that 66% of Latino registered voters in Arizona said they were more motivated to vote in 2020 after their experiences with pandemic-related job losses or pay cuts. The Biden campaign began consulting Latino Decisions on Latino outreach in July, according to a campaign spokeswoman.
Still, Latinos historically vote at lower rates compared with the general electorate. In 2018, turnout was about 47% in majority-Latino areas of Maricopa County, according to the Journals analysis. That was lower than the countywide turnout of 64.5%.
Rosie Abril, a 63-year-old retiree, said she expects turnout to be higher this year just because of who is running for president. Ms. Abril, an enthusiastic supporter of Mr. Biden, said that anyone who watches the news and keeps up with current events should be supporting the former vice president. She said she sees little need for the Democratic organizers who were in her Phoenix neighborhood in past cycles.
I think theyre gonna vote Biden no matter what just because of what were witnessing, she said of her fellow Latinos.
Meanwhile, the events of the last four years are exactly why Sandra J. Serna, a 60-year-old clinical medical social worker, is planning to vote for Mr. Trump after supporting Hillary Clinton in 2016.
Democrats spend so much time tearing down our country when Trump is focused on the progress of our economy, and to rebuild our country, she said.
While Republicans are reaching out to voters in person, Biden for President is conducting digital, text-message and phone outreach seven days a week concentrated in areas with large Latino populations in Arizona, according to a spokesman. The campaign has also released Spanish and English-language ads in the state. The aide said the campaign was basing its decisions on advice from public health experts.
Democrats will need to attract voters like Abigail Aramburo. Ms. Aramburo, 30, works in a plasma center, and will be voting in her first presidential election after becoming a U.S. citizen in 2017.
Mr. Biden believes in our values and whats important for me and my family, she said, listing immigration, public health and racial justice as key for her and her husband.
When we start a family we would like our children to be welcome and safe, she said, adding that Mr. Trump was creating a hostile environment.
Phoenix resident Paul Vargas, 50, is leaning toward Mr. Trump because of the religious-liberty policies his administration has put in place and support for a wall along the southern border. However, Mr. Vargas, a pastor who preaches to the homeless and people recovering from addiction, isnt happy with the presidents response to the pandemic.
No decision is a bad decision, and sometimes…what our president has done has had no decision or took too long to make a decision, he said.