The race in a state with a recent history of close elections is among a handful of contests that will determine how large a Republican majority Trump will work with in the Senate when the president-elect returns to the White House next year. The GOP clinched the Senate majority Tuesday night, retaking it from Democrats who held it for four years.

It is a test of the strength of the anti-Trump coalition that has powered the rise of Democrats in Arizona, which was reliably Republican until 2016. Arizona voters have rejected Trump and his favored candidates in every statewide election since then. The presidential contest was too early to call in Arizona after Trump defeated Democrat Kamala Harris in most of the seven other battlegrounds.

Gallego led Lake in early returns, which included a combination of mail ballots received and counted before Election Day and those cast in-person on Tuesday.

Gallego expressed confidence when he spoke to Democrats on Tuesday night in Phoenix, though the race remained too early to call early Wednesday with about a million ballots remaining to be counted.

"We had a mantra on this campaign: Go everywhere and talk to everyone," Gallego said. "And that's exactly what we did. We didn't take one vote for granted."

In a break with tradition, Lake and the Arizona Republican Party did not hold an election night party. She posted about results in the presidential race and shared complaints from others about the pace of vote counting in Maricopa County but did not say anything about her own race.

The winner of the Senate race will replace Kyrsten Sinema, whose 2018 victory as a Democrat created a formula that the party has successfully replicated since.

Sinema left the Democratic Party two years ago after she antagonized the party's left wing. She considered running for a second term as an independent but bowed out when it was clear she had no clear path to victory.

Gallego maintained a significant fundraising advantage throughout the race. He relentlessly attacked Lake's support for a state law dating to the Civil War that outlawed abortions under nearly all circumstances. Lake moved to the middle on the issue, infuriating some of her allies on the right by opposing a federal abortion ban.

Gallego portrayed Lake as a liar who will do and say anything to gain power.

He downplayed his progressive voting record in Congress, leaning on his up-by-the-bootstraps personal story and his military service to build an image as a pragmatic moderate.

The son of immigrants from Mexico and Colombia, Gallego was raised in Chicago by a single mother and eventually accepted to Harvard University. He enlisted in the U.S. Marine Corps Reserve and fought in Iraq in 2005 in a unit that sustained heavy casualties, including the death of his best friend.

If elected, he would be the first Latino U.S. senator from Arizona.

Lake became a star on the populist right with her 2022 campaign for Arizona governor.

She has never acknowledged losing the race and called herself the "lawful governor" in her 2023 book. She continued her unsuccessful fight in court to overturn it even after beginning her Senate campaign and as recently as last week refused to admit defeat in a contentious CNN interview.

But while visiting a polling place Tuesday, she told reporters, "I will accept the results of the election" this year.

Her dogmatic commitment to the falsehood that consecutive elections were stolen from Trump and from her endeared her to the former president, who considered her for his vice presidential running mate. But it has compounded her struggles with the moderate Republicans she alienated during her 2022 campaign, when she disparaged the late Sen. John McCain and then-Gov. Doug Ducey.

She tried to moderate but struggled to keep a consistent message on thorny topics, including election fraud and abortion.

Lake focused instead on border security, a potent issue for Republicans in a state that borders Mexico and saw record numbers of illegal crossings during Democratic President Joe Biden's administration. She promised a tough crackdown on illegal immigration and labeled Gallego a supporter of "open borders." She also went after his personal life, pointing to his divorce from Kate Gallego shortly before she gave birth. His ex-wife, now the mayor of Phoenix, endorsed Gallego and has campaigned with him.

Lake spent the last weeks of the campaign trying to win over voters who are backing Trump but were not sold on her.

Close to 4 in 10 Arizona voters said the economy and jobs are the top issue facing the country, according to AP VoteCast, a sweeping survey of more than 110,000 voters nationally, including more than 4,000 voters in Arizona. About one-quarter of Arizona voters said immigration is the most pressing issue, and about 1 in 10 named abortion.

Roughly half of Arizona's voters viewed Lake unfavorably, including about 4 in 10 who said they had a very unfavorable view of her, according to AP VoteCast. Roughly 4 in 10 voters viewed her favorably.

About half of voters held a favorable view of Gallego, and about 4 in 10 said they had a negative view of him.

Meanwhile, Arizona had two of the closest races for U.S. House, where Republicans David Schweikert and Juan Ciscomani sought reelection in districts that voted for Biden in 2020. Both races were too early to call.

Schweikert, now in his seventh House term, faces a challenge from former three-term Democratic state lawmaker Amish Shah in Arizona's 1st District, which includes north Phoenix, Scottsdale, Fountain Hills and Paradise Valley.

While Republicans hold a voter registration advantage in the affluent district, it has trended toward the center as college-educated suburban voters have turned away from Trump, reluctantly voting for Democrats or leaving their ballots blank. Redistricting ahead of the 2022 midterms accelerated the trend.

Schweikert won reelection by just 3,200 votes in 2022 against a relatively unknown challenger who got minimal support from national Democrats. Shah, an emergency room doctor, emerged as the primary winner among a field of six Democrats.

In the 6th District, Ciscomani is seeking a second term in a rematch against Democrat Kirsten Engel, whom he defeated by 1.5 percentage points in 2022. The district, which includes a stretch of the Arizona-Mexico border, runs from Tucson east to the New Mexico state line.

Ciscomani, a former aide to Ducey who immigrated from Mexico as a child, calls border enforcement his top priority but has distanced himself from Trump's anti-immigrant rhetoric.

Engel, a law professor at the University of Arizona and a former state legislator, has pointed out Ciscomani rejected a major bipartisan border bill in February that would have overhauled the asylum system and given the president new powers to expel migrants when asylum claims become overwhelming.

Republican Rep. Eli Crane in the 2nd District, a Republican-leaning district that covers vast swaths of rural Arizona and a few exurbs of Phoenix, faced a spirited challenge from Democrat Jonathan Nez, the former Navajo Nation president. Crane, a former Navy Seal, aligned with far-right House members against former GOP House Speaker Kevin McCarthy.

Of Arizona's nine representatives in Congress, six are Republicans and three are Democrats.