Darling Democratic U.S. Senators Bernie Sanders and Elizabeth Warren rallied hundreds of supporters in Boston to keep their progressive message alive while calling for a “fundamental transformation” of the Democratic Party from a club for liberal coastal elites to a movement that fights for the working class.

“We need a party which is a grass-roots party,” Sanders told the more than 1,500 supporters packed into the Orpheum Theater, “a party where candidates are talking to working people — not spending their time raising money from the wealthy and the powerful. The Democratic Party can no longer afford to be a party of New England and of the West Coast. We have to be a 50-state party.”

The former presidential candidate and U.S. senator from Vermont also shared his bewilderment over President Trump’s unexpected victory in the 2016 presidential election and the sway that Republican lawmakers still have in U.S. politics.

“How in God’s name do they win elections?” Sanders asked. “The reason is, in my view, that the time is long overdue for a fundamental restructuring of the Democratic Party.”

He called on everyone to get involved in the political process.

“Despair is not an option,” Sanders said. “I have not the slightest doubt that when we stand up and educate and organize and grow the union movement that when we stand together it is not going to be a victory for us — it is going to be a rout.”

Sanders filled the theater as part of his Our Revolution campaign, which is a remnant of his unsuccessful primary run and is aimed at pressing the progressive agenda and pushing for a $15 an hour minimum wage, paid leave, lowering higher education costs, criminal justice reform, protections for immigrants and regulating Wall Street.

Warren, who introduced Sanders, said Democrats need to be scrappy as they fight Trump’s agenda but warned they “can’t shoot at everything that moves.”

“We don’t have the tools,” Warren said. “Republicans have the White House. They’ve got the Senate. They’ve got the House of Representatives, and the number of tools we’ve got down in Washington on our side are limited, but that means exactly one thing, and that is: We are not going to be able to go in Washington and do this on our own, it’s going to take all of us in this fight.”

Warren highlighted the Democrats’ victory last week as Trump’s health care bill was hastily pulled before a doomed vote in the House, saying Republicans feared the blowback from constituents who preferred Obamacare to the American Health Care Act.

That victory aside, Warren said Republicans are busy in Washington repealing regulations.

“They’ve been busy,” Warren said.” It’s like a snowstorm and a tornado and a hurricane all happening at the same time.”