DES MOINES, Iowa-Just three days after Hillary Clinton visited the presidential testing grounds of Iowa, Vice President Biden was right behind her with a populist speech that sounded at times like it was 2016. Although this trip was an official White House visit, in Iowa the topic of presidential politics can't be avoided.

Biden's address focused on raising the minimum wage and making life better and fairer for the middle class. He came to the Iowa Capitol to help launch a nationwide tour of the liberal group "Nuns on the Bus." The vice president joined about a dozen nuns on stage who are heading out their rolling nunnery on a 10 state, 36 city tour of the country registering voters and preaching their message of social justice.

Biden, the nation's first Catholic vice president, noted his 12 years of Catholic education telling the crowd of about 300, "I was asked by the press why am I going out with Nuns on the Bus? I said because they are nuns. It's a simple proposition," adding to laughs, "I woke up every morning saying, 'Yes sister, no sister, yes sister, no sister.'"

He thanked the nuns for their work for health care reform saying in his signature colorful style, "The Nuns on the Bus fought like the devil for health care."

(Charlie Neibergall/AP Photo)

The audience cheered Biden who appeared with his sleeves rolled up on a warm, sunny Iowa day, but Hillary Clinton cast a shadow over the appearance.

Mike Winjum was wearing an Obama Biden T-shirt and enthusiastically spoke about how his father still talks about meeting Biden at last year's Harkin Steak Fry. He called the vice president a "great guy," saying "when he talks, people listen." But, when asked about whether he could caucus for Biden in 2016, he didn't hesitate: "Nope, I'm for Hillary. If Hillary jumps out, I'll be for Joe. He's number two."

Arloene Yungclas was at the event to celebrate her 80th birthday and although she likes the vice president, she said without a pause, "I'd like to see a woman be president of the United States and I think she (Clinton) is pretty knowledgeable about the world."

Her husband Jim agreed saying Biden is "probably" in Iowa because of possible presidential ambition, but "I would like to see a woman become president and Hillary would be a good president, she would be a good representative for us."

Mazie Johnson, a Democratic activist, was wearing a blue "Ready for Hillary" T-shirt.

"I am personally a huge fan of Hillary, I'm very supportive of what she is doing for women in the political world. She brings a lot of power and she also has an incredible track record of supporting fellow women, so I would absolutely say I am very supportive of Hillary," Johnson said.

On Sunday, Clinton returned to the first caucus state of Iowa for the first time since 2008 when she came in an embarrassing third in the Iowa caucuses behind Barack Obama and John Edwards. Over 6,000 people attended the Harkin Steak Fry Sunday where she headlined, along with former President Bill Clinton.

An early 2016 poll released this week from CNN/Opinion Research showed Clinton with a 38 point lead in the Iowa caucuses, with 53 percent to Biden's 15 percent.

Biden, who hasn't ruled out another presidential bid, made no mention of Clinton, but did at times sound like he was on his third presidential campaign trail railing against income inequality, as well as restrictions on voting rights.

This was Biden's first trip to the state since the last Harkin Steak Fry last year. He will hold a photo line fundraiser for multiple candidates while in Des Moines, but he won't stump for any 2014 Democratic candidates, including Bruce Braley who is running to succeed Harkin in the Senate. A poll out today from Quinnipiac University showed his Republican rival Joni Ernst with a six point lead.

After his speech, Biden boarded the nuns' bus, stopping at the Waveland Café, a Des Moines diner. He added his signature to the side of the bus, signing it with a black Sharpie.

The Republican Party of Iowa issued a statement today accusing Biden of using taxpayers for a campaign stop.

"The Vice President's office billed the trip as official business, but it featured all the hallmarks of a partisan Democrat campaign rally," the statement said.