Washington (AFP) - Bernie Sanders arrived in Congress in 1991 pledging to fight growing economic disparity, improve health care and education and reel the United States in from its involvement in "unnecessary" foreign wars.
A quarter century later, the self-described socialist senator from Vermont will bring a similar message to the American people as he hits the campaign trail -- this time as a candidate for president to succeed Barack Obama.
Running to the progressive left of declared Democratic candidate Hillary Clinton, Sanders wants to end tax breaks for the very wealthy, and is fiercely opposed to the huge trade pact under negotiation with Asia-Pacific nations, saying the deal would cost "millions of decent-paying" American jobs.
Disheveled, with a no-nonsense and occasionally gruff demeanor, and seemingly always in a hurry, the 73-year-old Vermonter is hardly shy about taking on the political establishment.
In 1987, running for re-election as mayor of Burlington, he defeated a candidate backed by the Democratic and Republican parties.
In 2016 he will have bigger challengers for the White House -- namely Democratic frontrunner Clinton, the former first lady and secretary of state -- and experts put his chances of victory at slim to none.
But in a rushed eight-minute appearance on the US Capitol lawn Thursday, Congress's longest-serving independent insisted he was "in this race to win."
Sanders, who caucuses with Democrats and is expected to run as a Democrat, is little known outside political circles and his home state of Vermont, where he will roll out a formal campaign launch next month.
He said he relishes the chance to go toe-to-toe with her in "serious debates over serious issues -- not political gossip."
He quickly earned a campaign welcome from his chief rival.
"I agree with Bernie. Focus must be on helping America's middle class. GOP would hold them back," Clinton wrote in a tweet. "I welcome him to the race."
- 'Immoral' economics -
For years Sanders has warned of the growing economic gap in America, stressing that "millionaires and billionaires" run a rigged system that benefits the wealthy at the expense of millions of working-class and poor citizens.
"Ninety-nine percent of all new income generated in this country is going to the top one percent," he said Thursday.
"That type of economics is not only immoral, it's not only wrong, it is unsustainable."
In 2010, during an eight-hour Senate speech, he launched a withering attack on the rich and Republicans in particular.
"I am talking about a war being waged by some of the wealthiest and most powerful people against working families, against the disappearing and shrinking middle class of our country," he fumed.
"The billionaires of America are on the warpath. They want more and more and more."
Sanders said recently implemented laws that relaxed campaign finance rules have proved "disastrous," allowing wealthy donors like the Koch brothers, billionaire industrialists who have contributed hundreds of millions of dollars into election campaigns, to "buy elections and candidates."
Sanders, born September 8, 1941 to a family of Polish Jewish immigrants, campaigned for civil rights reforms in the 1960s before entering politics.
He eventually won a congressional seat in 1990. He voted against authorizing military force in Iraq in 1991 and again in 2002, when Clinton voted in support of the Iraq war resolution.
In one of his first speeches as a member of the House of Representatives, in 1991, he foreshadowed many of the US challenges of the 21st century.
"At a time when this nation has a $3 trillion debt and is looking at the largest deficit in its history, has a banking system on the verge of collapse, (and) a health care system no longer working for ordinary Americans... it is my belief that a war in the Persian Gulf now, an absolutely unnecessary war, would be a terrible mistake that this country would regret for decades to come," he said at the time.