At a rally in Colorado last week, Hillary Clinton urged attendees to call their friends in other western states like Utah, Nevada and Arizona.

On Monday her campaign announced it was sending her most famous friend, Michelle Obama, to campaign in Arizona on her behalf – the vanguard of a $2 million campaign investment in the deep red state made competitive in large part by Donald Trump’s stumbles.

On a conference call Monday, Clinton campaign manager Robby Mook told reporters Mrs. Obama would follow other high profile surrogates Sen. Bernie Sanders and Chelsea Clinton into the Grand Canyon State. There are not yet concrete plans to send Mrs. Clinton.

The Real Clear Politics average of polls in Arizona shows Clinton trailing by just one point. No democrat has won Arizona since Bill Clinton carried it narrowly in 1996 – which was the only time in the last 40 years the state has gone blue.

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Republican strategist Rich Beeson, who lives in Colorado and has extensive experience in western states, said Arizona’s large and increasingly active Hispanic population hold Clinton’s key to victory.

In Maricopa County, the state’s largest, lightning rod Sheriff Joe Arpaio is locked in a tough reelection battle. The high anticipated turnout in that race could help Clinton generate enthusiasm among Hispanic voters.

Trump regularly cites “Sheriff Joe” as an advisor and inspiration on immigration issues.

“There’s a better than even chance [Clinton] wins Arizona,” Beeson said, should Trump not quickly pull out of his downward spiral.