And then there were 10. Elizabeth Warren, the veteran progressive senator, joined a crowded Democratic race on Saturday by announcing her 2020 presidential campaign with a populist challenge to Donald Trump. “The man in the White House is not the cause of what is broken, he is just the latest and most extreme symptom of what's gone wrong in America,” she said. “A product of a rigged system that props up the rich and powerful and kicks dirt on everyone else. So once he's gone, we can't pretend that none of this ever happened.” Although she has been campaigning for weeks Mrs Warren formally entered the race with a speech in Lawrence, Massachusetts, the site of one of America’s most famous labour strikes. The announcement gave her a chance to find oxygen for her message amid a busy, boisterous field fighting it out largely on the left of the party. But the entry of an acknowledged Leftist heavyweight serves to reinforce unease among some Democrats that they may struggle to unseat a president who has proved surprisingly effective at elections if they cannot attract centrist voters. Jeanne Zaino, professor of political science at Iona College, said it was the classic primary versus general election dilemma. As the most authentically progressive candidate to enter the race so far, Mrs Warren would appeal to many Democratic primary voters while exciting Republicans who would relish the chance to brand her as a socialist candidate. “The question is can she raise the money to take Trump on ... and if she runs against him can he still find a pathway through the Rust Belt? Whoever beats Trump is going to have to find a way to break his stranglehold on the Rust Belt where he did so unexpectedly well,” she said. It all comes after a bruising time for Mrs Warren. She apologised three times during the past week alone for previously identifying as a native American. The controversy erupted at the end of last year when she publicly announced that a DNA test revealed evidence of her native American identity only for the Cherokee Nation to say that it was wrong to use such tests to claim tribal membership. Her critics were quick to use the issue to ridicule her again. “Today Elizabeth Warren, sometimes referred to by me as Pocahontas, joined the race for President,” Mr Trump wrote on Twitter. “Will she run as our first Native American presidential candidate, or has she decided that after 32 years, this is not playing so well anymore? See you on the campaign TRAIL, Liz!” The White House declined to clarify his comments but some commentators suggested his words contained a reference to the Trail of Tears, a series of forced relocations of native American tribes in the 19th century. Donald Trump Jr used Instagram to stir things further: “Savage!!! Love my President.” Even the actor Rob Lowe joined the mockery, suggesting that she would bring new meaning to the role of “commander in chief” in a tweet that was later deleted. However, the ugly ridicule is a reminder that Mrs Warren enters as one of her party’s more recognisable figures. The 69-year-old former Harvard lecturer has spent the past decade in the national spotlight, after her expertise in bankruptcy law saw her emerge as a consumer activist during the financial crisis. She ran for the Senate in 2012, unseating a Republican incumbent in Massachusetts. And she became something of a feminist folk hero after the Senate voted to silence her objections during confirmation hearings and Mitch McConnell, the Republican majority leader, tried to blame Mrs Warren for disruption with the phrase: “Still she persisted.” Since then Mrs Warren has honed a message that includes Medicare for All – an expansion of government-funded health care – a 2 per cent wealth tax on those with $50 million (Dh183m) or more, and higher wages for workers, all lubricated with attacks on lobbyists, special interests and Wall Street. “When government works only for the wealthy and the well-connected, that is corruption plain and simple,” she said in a launch speech delivered against a backdrop of red brick mill buildings. “Our fight is to change the rules so that our government, our economy and our democracy work for everyone.” Of the declared candidates, she places second only to Kamala Harris, the California senator who has won plaudits for a slick campaign launch, in the most recent Real Clear Politics polling average. But both lag far behind Joe Biden and Bernie Sanders, who have not yet declared but whose high name recognition means they are dominating early polling. At least a dozen more names are considering runs, with an eleventh candidate – Amy Klobuchar – expected to declare by the end of Sunday. But Mrs Warren’s backers insist she has a vital quality that can set her apart from such a crowded field. As Ed Markey, her colleague as Massachusetts senator, put it: “The good news is that no one knows how to get under Donald Trump's skin better than Elizabeth Warren.”