WASHINGTON -- U.S. Sen. Cory Booker's voice was rising.

"The question is not what they are going to do, it's what we are going to do," he said at a Democratic fundraiser here. "We in this nation have work to do. Let us march. Let us march to organize. If we go together, we will bring this country forward,"

"America, marching onward!" he concluded as the crowd rose to its feet.

Booker's address rallied the Democratic troops Wednesday night in a way that two other potential 2020 Democratic presidential candidates failed to do at the event.

Neither U.S. Sen. Elizabeth Warren of Massachusetts -- clearly the crowd favorite at the start -- or U.S. Sen. Kirsten Gillibrand of New York stirred up the 600 people in the audience the way Booker did.

For Booker, the speech was reminiscent of his well-received address at the 2016 Democratic National Convention for its oratory.

This time around, Booker invoked the demonstrations of the past, against slavery, for a woman's right to vote, for civil rights, for the ability of workers to organize, and said such activism is needed again this November.

"We have a lot of marching to do in this country," Booker said. "We, the good people, are going to stand up. We, the good people, have to be ready to march."

The Democrats' IWillVote effort aims to reach 50 million voters, and Wednesday's dinner was the first of several events scheduled to raise money for the campaign.

Such efforts take on added importance in off-year elections, when Democratic turnout traditionally declines compared with presidential years. That helped Republicans win control of the U.S. House in 2010 and the Senate four years later.

This time around, strong Democratic turnout last year led to the party winning a U.S. Senate seat in deep-red Alabama and gubernatorial elections in New Jersey and Virginia, and capturing several Republican-held seats in New Jersey's legislature and its municipalities.

The party is counting on a similar surge in 2018 with control of the Senate and House is at stake. Democratic hopes have been fueled by the continuing unpopularity of President Donald Trump.

All of the candidates delivered lines guaranteed to receive applause from the partisan crowd, talking about issues such as health care, women's rights, gay and lesbian rights, and the rights of unauthorized immigrants brought to the U.S. as children to remain in the U.S.

Warren, welcomed with the loudest ovation of the three potential 2020 candidates, said she has contributed to every state party in order to help them get out the vote this fall.

She talked about the need for Democrats to reach out to people who are hurting economically, many of whom backed Trump in 2016.

"These folks are hurting and they're angry," Warren said. "I want us to be the party that picks the fights on their behalf. Let's kick some butt."

Gillibrand received the least enthusiastic response, even as she talked about the importance of black women voters, whose turnout helped deliver the Alabama Senate seat to Democrat Doug Jones, and how Texas is about to send two Hispanic women to the U.S. House.

"It is the women who are holding our democracy together in these dangerous times," she said.

Jonathan D. Salant may be reached at jsalant@njadvancemedia.com. Follow him on Twitter @JDSalant or on Facebook. Find NJ.com Politics on Facebook.