"Puerto Rico has not been treated with respect," she said. "It is insulting. It is disrespectful. This ugliness has gone far enough. Puerto Rico has suffered enough. We will not allow anyone to sabotage your recovery, not even the president of the United States."
Democrats are using official trips to Puerto Rico as an opportunity to criticize the Trump administration for how it responded to the hurricane and its aftermath. Last week, former housing secretary Julian Castro, who has declared himself a candidate, visited the island and toured communities still struggling more than a year after the storm.
Janina Cabret, a 28-year-old San Juan resident who attended Warren's event, said she hopes whoever wins isn't delivering empty promises about helping the island.
"Even though they use it for marketing, at least it puts Puerto Rico on the map," she said.
Warren reminded the crowd that she voted against a 2016 financial aid package that created a federal control board to oversee the debt-burdened island government's finances, a body that some complain has imposed an excessive amount of austerity. She also referred to White House comments on Puerto Rico, including a recent one opposing $600 million in nutritional assistance as "excessive and unnecessary," which angered Gov. Ricardo Rossello's administration.
The senator also talked about the island's political status, long a key issue for many Puerto Ricans, though five referendums over the years have shown no clear consensus for statehood, the current territorial status or independence.
"Puerto Rico deserves self-determination on this question, and I will support the decision of the people of Puerto Rico," she said.
Warren also called for auditing Puerto Rico's huge public debt, strengthening unions, protecting the island from climate change, and supporting full child tax credits, Medicaid funding and nutritional assistance for islanders, all things that many Puerto Ricans have long demanded.
"Puerto Rico's experience in recent years reflects the worst of what Washington has become, a government that works great for the rich and powerful, and not for anyone else," she said as she mentioned drug companies, student loan outfits, fossil fuel companies and Wall Street bankers. "We need to take back our federal government from the wealthy and well-connected and return it to the people."
Warren said she would demand that anyone running for federal office post their tax returns online as she has and touted her anti-corruption legislation, which in part calls for ending lobbying and stopping federal lobbyists from giving money to elected officials.
She also charged that Trump's administration has used its power to inflict cruelty on immigrants and people of color. "With Trump, cruelty is not an accident, it is part of the plan," she said.
The audience gave Warren a standing ovation at the end of her speech, many of them tourists thrilled that their visit coincided with hers.
Vandy Young, a tourist from Maryland, said she is hopeful about a presidential bid by Warren.
"I've been waiting for her to run," she said. "She's one of the few candidates who can stand up to Trump. She's not afraid of him."