WASHINGTON — Sen. Elizabeth Warren, an advocate of reining in America’s military budget and commitments around the globe, on Monday took the first major step toward launching a widely anticipated campaign for the presidency.

While Warren’s banking her reputation as a populist fighter can help her navigate a Democratic field that could include nearly two dozen candidates, she has also boosted her global affairs and national security credentials in recent years, in part by joining the Senate Armed Services Committee.

“No matter what our differences, most of us want the same thing,” the 69-year-old Massachusetts Democrat said in a video, which highlights her family’s history in Oklahoma and military family ties. “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 announcement comes weeks after Warren made a foreign policy speech at American University calling for a smaller defense budget, a pullout of U.S. troops from Afghanistan and a “no first use” nuclear weapons policy.

By linking her foreign policy with her left leaning economic views, Warren may win over liberal primary voters, but it’s unclear how this will play with moderate voters concerned with terrorism and actions by Russia and China.

“We need to refocus our international economic policies so that they benefit all Americans, not just wealthy elites,” she said in the American University speech. “At the same time, we must refocus our security policies by reining in unsustainable and ill-advised military commitments and adapt our strategies overseas for the new challenges we’ll face in this coming century.”

Warren has championed defense spending in her home state, but she used the speech to condemn America’s “bloated defense budget,” saying it’s time to end “the stranglehold of … the so-called Big Five defense contractors” as evidenced by President Donald Trump’s friendliness toward Saudi Arabia and its war in Yemen.

“The defense industry will inevitably have a seat at the table — but they shouldn’t get to own the table,” Warren said. “It is time to identify which programs actually benefit American security in the 21st century, and which programs merely line the pockets of defense contractors — then pull out a sharp knife and make some cuts.”

Where to cut? Warren has called for no new nuclear weapons, extending the New START Treaty through 2026 and a no-first-use policy for nuclear weapons. When Trump is undermining arms control agreements, she said, the U.S. “should not spend over a trillion dollars to modernize our nuclear arsenal."

Warren burst onto the national scene a decade ago during the financial crisis with calls for greater consumer protections. She quickly became one of the party’s more prominent liberals, even as she sometimes fought with Obama administration officials over their response to the market turmoil.

Now, as a likely presidential contender, she is making an appeal to the party’s base. Her video did not touch on foreign policy or national security, but noted the economic challenges facing people of color and showed images of a women’s march and Warren’s participation at an LGBT event.

In an email to supporters, Warren said she’d more formally announce a campaign plan early in 2019.

Warren is the most prominent Democrat yet to make a move toward a presidential bid and has long been a favorite target for Trump, particularly amid controversy over her claims of Native American heritage.

Warren enters a Democratic field that’s shaping up as the most crowded in decades, with many of her Senate colleagues openly weighing their own campaigns, as well as governors, mayors and other prominent citizens. One of her most significant competitors could be Sen. Bernie Sanders, a Vermont independent who is eyeing another presidential run harnessing the same populist rhetoric.

Sanders, the ranking member of the Senate Budget Committee, has a history of challenging Pentagon spending, particularly the use of overseas contingency operations funding to skirt statutory budget caps.

Hosting Defense Secretary Jim Mattis and Pentagon Comptroller David Norquist at the panel in March, Sanders questioned the massive compensation packages of top defense contractor CEOs and demanded that the Pentagon end its waste and abuse of taxpayer funds following years of reports of fraud and mismanagement.

Warren has the benefit of higher name recognition than many others in the Democratic mix for 2020, thanks to her years as a prominent critic of Wall Street; she also originally conceived of what became the government’s Consumer Financial Protection Bureau.

She now faces an arduous battle to raise money and capture Democratic primary voters’ attention before Iowa casts its first vote, which is more than a year away. She has an advantage in the $12.5 million left over from her 2018 re-election campaign that she could use for a presidential run.

Warren’s campaign is likely to revolve around the same theme she’s woven into speeches and policy proposals in recent years: battling special interests and paying mind to the nexus between racial and economic inequities.

“America’s middle class is under attack,” Warren said in the video. “How did we get here? Billionaires and big corporations decided they wanted more of the pie. And they enlisted politicians to cut them a fatter slice.”

The Associated Press contributed to this report.