Until the most recent debate, the candidates for the Democratic 2020 presidential nomination scarcely discussed foreign policy. Last week, that changed — prompted in part by a cascade of international events, including the Ukraine scandal, President Trump’s abrupt withdrawal of U.S. forces from northern Syria, and Turkey’s immediate attacks.

So what do these Democrats have to say about national security? Here are some takeaways on who’s saying what and why it matters.

1. The “top” candidates talk the most about security policy.

The Democratic candidates have increasingly discussed foreign policy not just on the debate stage, but also on the campaign trail.

One way to track this is by checking how often security has been mentioned in the top candidates’ social media accounts, defining top candidates as those polling above 2 percent support nationally as of the first debate in late June. I collected tweets using the Twitter API and WorkbenchData to pick up references to well-defined foreign affairs, leaving off trade and immigration so as to focus on security-related issues such as Afghanistan, cyberwarfare, U.S.-Iran relations and North Korea.

The three top-tier candidates — using The Washington Post’s most recent ranking of front-runner Sen. Elizabeth Warren (Mass.), former vice president Joe Biden and Sen. Bernie Sanders (I-Vt.) — have been commenting comparatively often on security issues. Since the June debate, security was the topic of 15.2 percent of Biden’s tweets and 14.5 percent of Warren’s. That’s a significantly larger proportion than those from some of the candidates still working to establish themselves as viable, such as former Housing Secretary Julián Castro with 9.3 percent and Sen. Cory Booker (N.J.) with 9.1 percent.

Substantively, these messages often focused on the security implications of climate change, driven in part by CNN’s September climate town hall. But they also discussed the future of the Afghanistan mission, veterans’ issues, and U.S.-Russia relations.

2. Republicans’ advantage on national security has faded.

By talking about national security, the top Democratic candidates are working to craft images as potential commanders in chief. That’s more likely to succeed than in years past. Republicans no longer have the monopoly on appearing strong on national security, as traditional party “stereotypes” keep weakening.

In 2014, Gallup found that Americans were 23 percentage points more likely to say Republicans would do better than Democrats at protecting the country from international threats; by 2018, the gap had shrunk to only 6 points. This is compounded by the fact that public approval vs. disapproval for the president’s handling of foreign policy has seen a negative 10-percentage-point swing since summer 2018.

Both shifts are probably because the Trump administration’s foreign policy has been moving further from what most Americans say they want. For instance, compared with past U.S. positions, current policy is being seen by many scholars as more critical of NATO, which most Americans support; friendlier to Russia, which most Americans distrust; and abandoning efforts to slow climate change, an area where growing majorities of Americans want more government action.

During last week’s debate, the candidates took advantage of that growing gap between the Trump administration’s actions and general American opinion, charting a middle course between respecting the public’s skepticism about intervention abroad while remaining largely opposed to stepping back from key commitments.

The field’s two military veterans — Mayor Pete Buttigieg and Rep. Tulsi Gabbard (Hawaii) — clashed on the future of U.S. involvement in Syria. But most of the candidates rejected Gabbard’s vision for wholesale departure in favor of Buttigieg’s call for measured engagement. Even Warren, the party’s front-runner and advocate for a decreased presence in the region, remarked that the Islamic State could not be allowed purchase and that withdrawal would have to be done “the right way, the smart way.”

Meanwhile, nearly all the candidates talked about combating Russian political interference in U.S. elections. Biden aimed for the security “middle” by arguing most fervently in favor of renewing support to NATO allies. And Sanders argued for continued mitigation measures on climate change through support for policies like the Green New Deal. While Warren didn’t mention it in the debate, her platform specifically identifies the military as a venue for implementing climate action, calling for limiting military dependence on fossil fuels, hardening facilities against extreme weather and investing billions into research on “microgrids and advanced energy storage.”

3. The Syria withdrawal works to the Democratic candidates’ advantage

Almost unanimously, national security scholars and politicians — including many congressional Republicans — have opposed Trump’s withdrawal from northern Syria, which allowed Turkey to attack the United States’ Kurdish allies. Perhaps most notable has been the widespread outcry from the retired military community, from concerns over the treatment of U.S. allies to the implications for U.S. grand strategy. My own research has found that, despite widely held norms against political engagement, this community can be particularly influential in affecting public opinion on matters like armed intervention.

Both Booker and former congressman Beto O’Rourke noted the national security community’s disapproval, specifically mentioning retired general and Trump’s former defense secretary Jim Mattis. Invoking Mattis’s past remarks that the United States had two powers in foreign affairs — “intimidation and inspiration” — Booker called for relying on the diplomatic corps to “focus on the latter power.” And Biden similarly drew on the ex-military community’s disapproval for the decision when he explicitly noted that “commanders across the board, former and present, are ashamed” of the withdrawal.

As the Democratic field tightens in coming months, we can expect an even larger shake-up in how the candidates and parties position themselves on national security.

Michael A. Robinson (@m_robinson771) is an assistant professor of international affairs at the U.S. Military Academy at West Point and an active-duty Army strategist. He holds a PhD in political science from Stanford University, where his research focused on public support for foreign policy, partisan polarization and civil-military relations.

The views expressed are those of the author and do not reflect the official policy or position of the Department of the Army, the U.S. Military Academy, the Department of Defense, or any part of the U.S. government.