Sen. Elizabeth Warren announced Monday that she's running for president in 2020. In a press conference outside her Cambridge home on Monday, she addressed a gaggle of reporters and explained why she made the decision.

“America’s middle class is getting hollowed out, and opportunity for too many of our young people is shrinking,” said Warren. “So I’m in this fight all the way.”

When Warren was asked how she and Democrats could take back the message of income inequality that President Donald Trump used effectively in 2016, she responded: “We have to get out there and be clear about what we’re fighting for, and then we’ve gotta show that we’re willing to fight for it.”

Warren ignored questions about a head to head fight in the style of Trump, or if winning means rivaling his bombastic style of campaigning.

“I think the central part of winning this is getting out and talking with people about that we're fighting for," she said. "We want a government that works not just for the rich and powerful. We want a government that works for everyone.”

Postal worker Stanley Swan, delivering mail nearby, said he liked what he heard. “She seems very well rounded, well liked," he said. "She wants to help everyone so I'm all for it.”

In a video released earlier Monday, Warren announced that she was launching an exploratory committee for president.

"No matter what our differences, most of us want the same thing," Warren said in the video. "To be able to work hard, play by the same set of rules and take care of the people we love. That's what I'm fighting for and that's why today I'm launching an exploratory committee for president."

The senator also outlined some of her reasons for running, among them, economic inequality and fairness for working families.

“I’ve spent my career getting to the bottom of why America’s promise works for some families, but others who work just as hard slip through the cracks into disaster, and what I’ve found is terrifying," she said. "These aren’t cracks that Americans are falling into. These are traps.”

Warren, who is the senior senator from Massachusetts, was elected to the post in 2012, and recently won re-election against Republican challenger Geoff Diehl.

Warren’s campaign said she's hitting the road this month, with anticipated first stops in Iowa and New Hampshire. Campaign staff told WGBH News they are now focused on her schedule and suggested she will be campaigning all across the country, including states won by handily by Donald Trump in 2016.