Race is on, as Sanders raises $1.5 million during the 24 hours after announcing his campaign

The presidential campaign of U.S. Sen. Bernie Sanders is off to a strong start, raising $1.5 million in the 24 hours after he announced his plan on April 30 to challenge Hillary Clinton for the Democratic nomination.

That’s a hefty haul for the self-described democratic socialist. It exceeds donations received by Sens. Rand Paul and Marco Rubio during the first 24 hours after they announced runs for the Republican nomination.

Sanders told MSNBC’s Rachel Maddow that 35,000 people contributed an average of $43 via his website — BernieSanders.com. In addition, more than 100,000 people offered to volunteer for his campaign.

In characteristic Sanders fashion, the opening page on his website states, "Paid for by Bernie 2016. (Not the Billionaires)."

Sanders is an independent who caucuses with the Democratic. He's by far the most liberal candidate to announce a 2016 campaign for the White House. Although largely dismissed as a fringe-left leader, Sanders’ first-day take suggests that it’s possible for him to raise the $50 million he’d need to stage a credible presidential campaign.

But that’s small potatoes compared to the $1 billion that Clinton plans to raise.

Sanders’ candidacy was long expected, with political insiders accurately predicting he’d wait for to announce, which she did earlier in April.

While others have shown an interest in seeking the Democratic nomination, Sanders' announcement creates a contest. And his candidacy was cheered by leaders of many national and grassroots progressive organizations.

"With Sen. Sanders entering the Democratic primary, Americans can be sure that this election will include a robust and healthy discussion of fundamentally important challenges like tackling the climate crisis, getting big corporate money out of politics and investing to grow our clean energy economy," said Michael Brune, executive director of the Sierra Club. "On behalf of the Sierra Club’s 2.4 million members and supporters, we welcome Senator Sanders to the 2016 race and look forward to the debate on these issues in the months to come."

Ryan Greenwood of the National People's Action Campaign, a network of 30 grassroots groups in 17 states, said Sanders' "candidacy will shift the presidential debate toward meaningful measures to address growing economic and racial inequality, a democracy under attack, and a planet in peril. By running on a bold populist agenda, Sen. Sanders will not only help force candidates like Hillary Clinton to take sides, he will also create space for candidates running for office at every level to put people and the planet before corporate profits."

The 73-year-old Sanders, a native of Brooklyn, New York, served four terms as mayor of Burlington, Vermont, and has lived in the state since the mid-1960s. In college, he had been involved in the Student Nonviolent Coordinating Committee and joined the March on Washington. He then joined the influx of counterculture, back-to-the-land migrants to Vermont and held various jobs, including carpenter and filmmaker. He was elected mayor in 1981 and to Congress in 1990. Throughout his career, has focused on the shrinking middle class and growing wealth gaps in the United States.

Party leaders welcomed Sanders’ announcement.

Clinton tweeted, "I agree with Bernie. Focus must be on helping America's middle class. GOP would hold them back. I welcome him to the race."

U.S. Rep. Debbie Wasserman Schultz, Democratic National Committee chair, tweeted, "Sanders has clearly demonstrated his commitment to the values we all share as members of the Democratic Party.”

CALLING CARD MOMENT

U.S. Sen. Bernie Sanders took to the Senate floor in December 2010 and thundered for more than eight hours about a tax-cut package and Congress' failure to provide enough money, in his view, for education and social programs.

With his trademark sarcasm, he mocked the rich, yelling: “How can I get by on one house? I need five houses, 10 houses! I need three jet planes to take me all over the world!"

The speech was so popular it crashed the Senate video server. It was later printed in a small book.