Tulsi Gabbard gave Bernie Sanders an endorsement. He gave her a platform on war and peace.

KISSIMMEE, Fla. —The thousands of people who have streamed to Bernie Sanders’s rallies around the country in recent days have been treated to an opening act — Rep. Tulsi Gabbard of Hawaii — who arguably does more to articulate Sanders’s views on foreign policy than he does.

Gabbard, 34, who resigned as vice chairwoman of the Democratic National Committee last month to endorse Sanders for president, has been tasked with introducing him at recent events, including one here Thursday that drew more than 5,000 people.

Unlike the Vermont senator, who focuses heavily on domestic policy at his rallies, Gabbard is talking about U.S. entanglements abroad. And she doesn’t pull any punches when relaying what she sees as a crucial difference between Sanders and her party’s front-runner, Hillary Clinton.

“The choice before us is this,” Gabbard told the crowd here. “We can vote for Hillary Clinton and … get more of these interventionist, regime-change wars that have cost us so much, or we can vote for and support Bernie Sanders, end these counterproductive, costly interventionist wars and invest here at home, because we cannot afford to do both.”

Gabbard brings a noteworthy perspective to the task: She is one of the first female combat veterans to serve in Congress, and she talks about her service in Iraq as a formative experience.

“No one understands more how important peace is than those who’ve actually been there and experienced that high cost of war firsthand,” Gabbard said here. “During my first deployment to Iraq, I served in a medical unit where every single day that high human cost stared me back in the face.”

Gabbard’s endorsement of Sanders raised eyebrows last month, in part because of the potential political consequences of crossing Clinton, who seemed to be well on her way to the winning the Democratic nomination.

In an interview, Gabbard said that any political fallout was not part of her calculus. She said she was frustrated that issues of war and peace were not getting more attention in the presidential race and that she had not been able to change that in her position with the DNC. Like other party officers, she was expected to remain neutral in the Democratic primary.

“We need more people to start talking about it,” Gabbard said. “We need to hold the candidates accountable and press them on their positions.”

She said that the choice between Sanders and Clinton wasn’t a difficult one.

“I have learned how important it is that we have a commander-in-chief who exercises good judgment, who has foresight, who has the military mind-set to go and understand what the consequences of a military action is, to analyze that action and know what the results of that will be before that action is taken,” Gabbard told the crowd here. “It is the lack of that military mind-set that we have seen in our failed ventures in the Middle East, whether you’re talking about in Iraq, in Libya or now in Syria today.”

She said she trusts Sanders to “make those decisions about when and where our American military powers should be used and just as importantly, when and where it should not be used.”

During his stump speech, Sanders’s remarks on foreign policy are often confined to recounting his 2002 vote against the authorization of force in Iraq. Sanders concedes that Clinton, the former secretary of state, has a lot of foreign policy experience, but he points to his vote against the war to argue that he has better judgment than her. Clinton voted the other way while a senator representing New York, and she has since said that was a mistake.

When he took stage here on Thursday, Sanders thanked Gabbard, calling her “a great congresswoman.” And then he thanked her for being a leading voice “in the fight to make sure we do not get involved in perpetual warfare in areas we should not be.”