(CNN) Moments after news broke that Iran had fired missiles at US forces in Iraq Tuesday night, Elizabeth Warren took the stage in Brooklyn for her first joint campaign rally with Julián Castro .

Even before thanking Castro for his endorsement , Warren first addressed the breaking development : "This is a reminder of why we need to de-escalate tension in the Middle East. The American people do not want a war with Iran."

The moment captured how President Donald Trump's order to kill Iran's military commander Qasem Soleimani has abruptly thrust foreign policy to the forefront of the 2020 Democratic race , shining a new spotlight on candidates' foreign policy experiences and records, and sparking fresh debates about the use of military force and US interventions abroad. With the election now unfolding against a backdrop of conflict and war, for Warren, her ability to articulate her own vision on foreign policy will be particularly critical as she takes on rivals like former Vice President Joe Biden and Vermont Sen. Bernie Sanders , who have spent more time publicly articulating those ideas in their decades in public office.

As her national security credentials face their most strenuous test so far, Warren has been making a more explicit case about how she would revise American foreign policy -- and how her agenda abroad is linked to her agenda at home. A member of the Senate Armed Services Committee, Warren has weighed in frequently in recent days both on Iran and her foreign policy vision more broadly, slamming Trump as "reckless" and repeatedly stressing that the United States should not start another war in the Middle East.

CNN interviewed more than half dozen foreign policy veterans who have been quietly advising Warren and her team over the past year, as well as senior campaign aides. The network of informal advisers consulting with the Warren campaign is previously unreported. Collectively, these interviews paint a picture of a second-term senator who is deeply weary of US military interventions, resists drawing distinctions between domestic and foreign policies, and has attracted to her presidential campaign a number of career diplomats who say Washington, as one adviser described it, is in urgent need of a "substantial rethink" of how it conducts foreign policy.

Those who spoke with CNN described emails, group text chains and conference calls where they brainstorm responses to urgent international events, help draft campaign statements and policy papers, and flag developments that they believe should be top of mind for Warren and her senior aides. They coordinate closely with Warren's top foreign policy aide, Sasha Baker, former deputy chief of staff to ex-Secretary of Defense Ash Carter, who transitioned from Warren's Senate office to the White House campaign last year.

While the majority of the policy plans that Warren has released over the last year tackle domestic issues, several have been foreign policy-oriented, including a proposal last month on curtailing global financial corruption. Warren has also made a campaign pledge to not appoint donors and campaign bundlers to ambassadorship positions as president, and has called on her rivals to do the same.

"She has this theme for domestic policy which is about corruption and deep structural change and inequality," said Ilan Goldenberg, former chief of staff to the Special Envoy for Israeli-Palestinian Negotiations in the Obama State Department who has been advising the Warren campaign since the summer. "She wants to apply that to foreign policy writ large."

Yachts, corporations and corruption

Warren made clear, even before she became a candidate, that she would draw a close linkage between domestic and foreign policy.

She signaled as much in an early speech: Speaking to a packed hall on a college campus, Warren railed against policies that favor wealthy elites, corporations and special interests; deployed a metaphor about yachts; and made at least a dozen references to corruption.

But this was not a campaign stump speech -- Warren was not yet a presidential candidate. It was a rare foreign policy speech that the senator delivered in November 2018 at American University. To political observers, it appeared to be a clear signal that Warren was gearing up for a 2020 run -- she would launch an exploratory committee for president weeks later on New Year's Eve.

Warren has not made a foreign policy-focused speech since jumping into the 2020 race, and an aide told CNN that there are no plans at the moment to do so. That speech from more than a year ago, along with a lengthy article in Foreign Affairs magazine from around the same time, serve as two of the most detailed and recent blueprints of Warren's foreign policy vision.

Since then, there have been striking similarities in the language Warren used at American University and what she has said over the last year on the campaign trail. Corruption has emerged as the overarching theme of Warren's campaign for the White House, with the majority of her diagnoses on the domestic problems that face the country tracing back to it in some shape or form.

Her advisers stress that there is little daylight between how Warren views the gravest domestic and foreign policy challenges facing the country. One foreign policy aide on the campaign, who spoke on the condition of anonymity, described such a distinction as arbitrary.

"Anti-corruption: It runs through everything that she's talking about on both the domestic and foreign policy side," said Jarrett Blanc, former coordinator for the Iran nuclear implementation at the State Department and acting special representative for Afghanistan and Pakistan under President Barack Obama. "That question of corruption -- the ways that it damages our partners, destabilizes key countries abroad, damages our interests and our country -- that is a foreign policy question that needs to be acknowledged as such."

Blanc has assumed a lead role in corralling a group of outside foreign policy advisers helping the Warren campaign. According to the campaign, it includes Alexandra Bell, former senior adviser to the Under Secretary of State for Arms Control and International Security, Brittany Brown, former acting senior director for African Affairs at the National Security Council, Hady Amr, former deputy special envoy for Israeli-Palestinian negotiations, Mike Fuchs, former Deputy Assistant Secretary of State for East Asia and Pacific Affairs and Laurel Miller, former acting special representative for Afghanistan and Pakistan.

Non-military "tools in the toolbox"

The US operation that killed Soleimani has reinvigorated the debate over the use of American military force and interventions abroad. The question has dominated the 2020 Democratic contest, putting White House hopefuls on the spot on the controversial airstrikes that killed Soleimani, and what actions the Trump administration and Congress should take in its aftermath.

The development has prompted Warren to state repeatedly: No more wars in the Middle East.

Several of Warren's outside foreign policy advisers and an aide to the senator said minimizing the deployment of US military abroad and reevaluating what international challenges can and cannot be resolved with military force is central to Warren's foreign policy outlook. (Each of outside adviser that CNN interviewed emphasized that they did not speak on behalf of the campaign or candidate.)

"For years, senior leaders have done a disservice to our military by remaining mired in these conflicts and not being open with the American people about their cost," said Loren DeJonge Schulman, who served as senior adviser to Obama's national security adviser Susan Rice and has been advising the Warren campaign since last summer.

"We've put service members at enormous risk by asking them to solve problems without military solutions. Warren has no qualms calling this out," she said.

On the campaign trail, Warren tells voters that "it is time to bring our troops home," and regularly makes the case for exploring non-military, diplomatic actions to take, describing them as other "tools in the toolbox." She also frequently references her three brothers who are veterans, saying she has seen first-hand the sacrifices that military families make.

Over the summer, the senator released a proposal to reform the State Department -- as a part of that plan, she pledged to fill some of the senior-most positions there with career diplomats, double the size of the US foreign service and not give ambassador posts to donors and bundlers.

"She believes in staying engaged in the world but reinvigorating diplomacy as part of that and considering when the military is absolutely necessary and when the military is absolutely not necessary," said Robert Ford, former US ambassador to Syria.

'Now that I live here, I see it'

But even some of Warren's foreign policy advisers say it is her domestic agenda, as much as anything else, that has drawn them to her campaign.

The many years that Ford served as a career foreign service officer took him to war-torn, devastated areas around the world. When he retired in 2014, he and his wife settled down in Bangor, Maine. It was then, Ford said, that he saw up close some of the most urgent problems plaguing his home country.

He's driven by shuttered factories, wood mills and furniture manufacturers, witnessed the wrenching effects of the opioid crisis, and at his church in Bangor, St. John's Episcopal, where he serves lunch once a month to the needy, he's met struggling families, including single parents and their children.

"Now that I live here, I see it," Ford told CNN in a recent interview. "We have to help people at home. We can't be strong overseas if we have really deep structural weaknesses back here in the United States."

In her foreign policy speech at American University, Warren stated that "investments at home strengthen the economy, but these investments also serve national security." It's a sentiment she has reiterated on the campaign trail over the last year as she has released one domestic policy plan after another and embraced her campaign's unofficial campaign slogan, "I have a plan for that."

Ford said this philosophy was one of the major reasons that he has chosen to get behind Warren in the 2020 election, and he has been advising her team, with a focus on Middle East issues, since around Thanksgiving.

Other advisers and aides echoed that it has been made clear to them that Warren's foreign policy priorities stem from first and foremost directing resources and energy to combating challenges at home.

Dave Rank, former deputy chief of mission at the US Embassy to China who worked under five presidents, resigned from the State Department after the Trump administration withdrew from the Paris climate accord. In an interview, he pointed to the climate crisis as a vivid example of the US losing its sway abroad by failing to take action domestically.

"If we're not going to lead," Rank said, "China's not going to step forward." Rank has been advising the Warren campaign for several months.

"The country over which we have the most influence is the United States -- so I'm attracted to somebody who says that's where we should put our energy," he said. "Not that we should ignore the problems coming out of Beijing, but the road to fixing them to a large extent starts here."