Michelle Obama has proven to be Hillary Clinton's strongest, most powerful surrogate on the campaign trail when it comes to denouncing Donald Trump's fiery rhetoric.

After Trump asserted during the final presidential debate this week that he would keep voters "in suspense" by not committing to uphold the outcome of the presidential election, the First Lady strongly denounced his remarks to a crowd of 7,000 prospective voters in Arizona on Thursday. The traditionally conservative state has seen an influx of attention—and campaign ad money—turned its way after some polls indicated it could come into play as a battleground state this election season.

Obama urged voters not to become disillusioned by Trump's rhetoric and told them to go to the polls instead of staying home on election day. "That's the strategy. To make this election so dirty and so ugly that we just turn off the TV and say, 'We just don't want any part of it,'" Obama said. "So when you hear folks talking about a global conspiracy, and saying this election is rigged, understand that they are trying to get you to stay home. They are trying to convince you that your vote doesn't matter, and the outcome has already been determined and you shouldn't even bother to make your voice heard."

"They are trying to take away your hope," she added.

Obama then turned her attention to Trump's remarks this week that he would only accept the results of the election if he won.

"The voters decide who win elections, period. End of story. And when a presidential candidate threatens to ignore our voices and reject the outcome of this election, he is threatening the very idea of America itself. You do not keep American democracy 'in suspense,'" Obama said, referencing the phrase Trump used during Wednesday's debate. "Too many people have marched, and protested, and fought, and died, for this democracy. Please."