First lady Michelle Obama Michelle LeVaughn Robinson ObamaChicago's next mayor will be a black woman Obama portraits brought more than 1 million visitors to National Portrait Gallery in first year Barack and Michelle Obama announce new heads of their production company MORE, fresh off a fiery campaign speech many are calling among the best of the year, will take the case for Democratic presidential nominee Hillary Clinton Hillary Diane Rodham ClintonREAD: Cohen testimony alleges Trump knew Stone talked with WikiLeaks about DNC emails County GOP in Minnesota shares image comparing Sanders to Hitler Holder: 'Time to make the Electoral College a vestige of the past' MORE to the traditionally red state of Arizona on Thursday.

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Obama will headline an early-vote rally in Phoenix, where she will "lay out what is at stake in November” and urge Arizonans to cast early ballots for the Democratic ticket, the Clinton campaign announced Monday.

It’s another sign of the campaign’s efforts to make a play for Arizona, which has gone Republican in four consecutive presidential elections.

The Clinton campaign is turning to the first lady, who as emerged has her most powerful surrogate.

Obama’s takedown of Trump last week for boasting about his sexually aggressive behavior toward women earned praise from political strategists as one of the most effective stump speeches of the 2016 campaign.

They also lauded her address at the Democratic National Convention in Philadelphia.

The Clinton campaign is looking to use its financial advantage over Trump to make him spend time and money defending reliably Republican territory, including the Grand Canyon State.

It plans to spend an additional $2 million in the state on television and digital ads, as well as direct mail, campaign manager Robby Mook said Monday.

The campaign already has 32 offices and 160 staffers on the ground there.

Sen. Bernie Sanders Bernard (Bernie) SandersSenate Dems seek to turn tables on GOP in climate change fight Bernie Sanders Town Hall finishes third in cable news race, draws 1.4 million viewers Woman to undecided Biden: 'Just say yes' to 2020 bid MORE (I-Vt.), Clinton’s chief opponent during the Democratic primaries, on Tuesday will headline campaign rallies in Flagstaff and Tucson.

The campaign hopes that Sanders can motivate young voters to turn out for Clinton, who has struggled to generate enthusiasm among the voting group.

And former first daughter Chelsea Clinton on Wednesday scheduled to stump for her mother at Arizona State University in Tempe.

— Jessie Hellmann contributed.