On the same day Hillary Clinton was campaigning with Al Gore in Miami, President Obama was rallying for her in North Carolina.

Two days later, Michelle Obama would give her memorable speech in New Hampshire criticizing Donald Trump’s behavior with women, while Vice President Biden was campaigning for Clinton in Nevada.

The next week, Sen. Elizabeth Warren was touting the Democratic nominee in Ohio while Sen. Bernie Sanders rallied supporters for her in Nevada.

This is Clinton’s Army – a group of popular, powerful Democrats who have spread out across battleground states to criticize Trump and encourage early voting as part of their effort to win Clinton the White House.

It’s a stark contrast to the GOP nominee, whose most notable surrogates – Rudy Giuliani, Gov. Chris Christie, and Sen. Jeff Sessions – often campaign with the candidate or introduce him at rallies, though few other Republicans are willing to campaign for him.

GOP strategist Michael Steel of Hamilton Place Strategies, who has worked on several presidential campaigns, noted that Clinton “has the resources and experience of the entire Democratic Party at her disposal, while many, many experienced and talented potential GOP surrogates don't want anything to do with Donald Trump."

Another Clinton advantage is the surrogates’ popularity. An NBC/Wall Street Journal poll earlier this month found Michelle Obama had the highest approval rating of any political figure in the country at 59 percent. President Obama was at 51 percent and Clinton herself was at 40 percent.

It’s not just the popularity of these stand-ins – they offer Clinton strength where she is weak, can defend her better than she can defend herself, and encourage Democrats in early-voting states to cast their ballots.

Michelle Obama was able to address Trump’s issue with women in a way Clinton herself never could, given her husband’s history.

President Obama appeals to millennials and minorities. Plus he brings an energy and enthusiasm to the trail that Clinton cannot. In an event in Miami late last week, he was practically gleeful on the stump, throwing out zingers about Trump, laughing, pointing and rolling up his sleeves as he talked to the crowd.

Biden has a folksy charm that appeals to women and middle-class non-college-educated white voters, the latter group a bastion of Trump support.

And Warren and Sanders are heroes to the liberal left. The Vermont senator, who gave Clinton a run for her money in the primary, has appeared on college campus after college campus to help with the youth vote. And Warren, his Massachusetts counterpart, has taken to baiting Trump on Twitter.

With so many others doing the fighting for her, Clinton can look presidential and above the fray.

While campaigning for their party’s standard-bearer, the surrogates are also encouraging early voting in states that allow it, several of which are battleground areas.

Michael McDonald, an associate professor of political science at the University of Florida and founder of the Elections Project, which tracks turnout, predicted high turnout due to this effort.

“There are states that have very expansive early voting. In some of the key battleground states we’re going to see early voting at 50 percent, two-thirds or maybe even higher. And those states would be places like Florida, North Carolina, and Ohio, Iowa, Colorado, and Nevada,” he told RealClearPolitics’s “In the Arena” podcast.

President Obama was in Miami on Thursday, ahead of Florida’s early voting (which begins Oct. 29), to urge people to cast their ballots.

And who better to talk about the importance of voting in Florida than Al Gore.

“Your vote really, really, really counts,” he said at an event at Miami-Dade College, referring to his narrow 2000 election loss. “You can consider me as an Exhibit A.”

“Please, take it from me,” he said. “Every. Single. Vote. Counts.”

Michelle Obama has also raised this battle cry. At every campaign rally, she notes how few votes it could take in each state for the Democrats to lose.

“We need you to leave here with all the energy and get yourself and everyone you know registered to vote today. And we’re fortunate because the Clinton campaign is highly organized, so there are a number of volunteers here today who can help,” she said a rally in Charlotte, N.C., earlier this month.

Ironically, it is Biden and Sanders – two men who could have captured the nomination themselves – that have racked up the most appearances for Clinton. Biden has campaigned heavily for her in his native Pennsylvania but has also made stops in New Hampshire, Ohio and Nevada.

“I think I have campaigned for Hillary more than any person,” Biden said in the Granite State last week.

Sanders has been to college campuses all over the map, making stops in New Hampshire, Ohio, Pennsylvania, Minnesota, Iowa, and Maine.

Clinton spokesman Brian Fallon said the surrogates give the campaign a two-fold advantage.

“It’s a huge multiplier effect for us. It allows us to cover a lot more territory at the same time. On any given week now you’ve seen President Obama, the first lady, Senator Sanders, Senator Warren and the vice president panning out. But in addition to having all of those people provide a surround-sound of sorts about why Hillary Clinton would make a great president, they are also just extremely valuable validators,” he told RealClearPolitics earlier this month.

The Trump campaign didn’t respond to a request for comment, but communications director Jason Miller told the Washington Post last week: “There is a perception that Hillary has more surrogates out on the trail. I think that’s partially because she doesn’t campaign herself nearly as often as a typical candidate would. And there’s so little interest. She’s so boring that people might be looking for surrogates who are more exciting than her.”

Both candidates have had their families stump for them. Bill and Chelsea Clinton have made multiple appearances in swing states, as have Donald Jr., Eric, and Ivanka Trump.

But when Trump is in trouble, often his most effective surrogates step back.

When the Washington Post revealed the recording of the “Access Hollywood” interview that contained Trump making Lewd comments about women, his campaign manager, Kellyanne Conaway, canceled her already-scheduled Sunday show appearances. Giuliani appeared on them instead (although Conway did defend Trump in later interviews).

Trump’s popular daughter Ivanka didn’t defend her father’s remarks in her first appearance back on the campaign trail after the tape was revealed.

She later did so, however.

"Well, he recognizes it was crude language. He was embarrassed that he had said those things and he apologized. That's not language consistent with any conversation I have ever had with him certainly or any conversation that I have overheard, so it was a bit jarring for me to hear and he was very sincere in his apology," she said at a Fortune’s Most Powerful Women Summit in California.

But she also said at the same event: "I'm not a surrogate, I'm a daughter.”

Melania Trump, who has made notably fewer appearances on the campaign trail after her husband secured the nomination, was also late to defend him.

He was "egged on" into "boy talk,” she told CNN.

Speaker Paul Ryan canceled his one planned campaign appearance with Trump once the recording was released. No former GOP presidential candidate has appeared with the nominee.

Fallon said it’s notable Republicans won’t take that step.

“He gets more attention from the fact that so many Republicans are distancing themselves from him around the country than anything else. But surrogates are … a true measure of the overall health of the campaign,” he said. “It’s like a vital sign of how your campaign is doing, akin to your ground game operation or fundraising totals. So he is really testing the limits of how you can run an unconventional campaign the way that he is. We think that, at the end of the day, that having the fundamentals be in a good place -- like a vast surrogate operation, a strong field organization, running ads on TV – these are critical factors that are going to make a difference in this race.”