On Thursday, Hillary Clinton held her first joint rally with Michelle Obama. The first lady has become one of Clinton’s most valuable surrogates and her most effective political weapons against Donald Trump.

Michelle Obama is seen as so popular even Trump has never really attacked her. To see what the Clinton campaign cares about, watch where the first lady goes and what she says.

After hugging it out in North Carolina, Clinton posed a hypothetical question.

“Seriously, is there anyone more inspiring than Michelle Obama?” she asked.

It turns out, no. There’s not. A Fox News poll out this week shows Mrs. Obama with the highest favorability ratings of anyone in politics.

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In the last few months, the Clinton campaign has put that popularity to use. First, there was the standout speech at the DNC.

“Our motto is, when they go low, we go hi,” Mrs. Obama proclaimed on the convention stage in July.

Then, she responded to Trump’s comments about assaulting women during a campaign stop in New Hampshire.

“I have to tell you that I listened to all of this, and I feel it so personally,” she told the crowd. “And I’m sure that many of you do too, particularly the women.”

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Then, she responded to allegations of election fraud and helped open up a new battleground in Arizona.

“He is threatening the very idea of America itself, and we cannot stand for that,” she said.

When Mrs. Obama speaks at a campaign event, her message is one the Clinton campaign wants hammered home.

“So here’s what I’m asking you. Get out and vote. Get out and vote for Hillary. Get out and vote right now. Leave here, go vote,” she urged the crowd Thursday in North Carolina.

No word yet on where Mrs. Obama will go next week. Wherever it is, we’ll know what the Clinton campaign sees as its final test.