During the last Democratic debate, moderators from CNN failed to ask even a single question about climate change or clean energy. In fact, despite record global temperatures in the past months, extreme flooding from North Carolina to Scotland, and increasingly dire predictions about shrinking coasts and expanding deserts, there has been far too little conversation about climate change so far during the 2016 campaign.

Failing to address climate change is a mistake—one the party, the nation, and ultimately the world cannot afford to repeat at next Sunday’s fourth #DemDebate.

With Lindsey Graham out of the race, the Republican field is—at least until the eventual nominee might choose to rush to the center for the general election—effectively a wash for serious policy prescriptions on climate change. Between Sen. Ted Cruz inviting climate deniers to Congress, Sen. Marco “I’m Not a Scientist” Rubio’s wishy-washiness, and frontrunner Donald Trump’s characteristically confusing and wrong conviction that climate change doesn’t exist, there is scant hope for the GOP to offer anything substantive on this front.

But “because the Republicans aren’t doing it” isn’t the only reason for the Democrats to talk about climate change; if that were our only criteria for debate topics, each one would take days.

For one thing, fighting climate change is a national security issue. The men and women of the U.S. military are the ones deployed to deal with the consequences of climate change, whether that means resource shortages that empower extremist groups in already fragile states, or natural disasters requiring urgent humanitarian aid. And whatever love some lobbyists may have for fossil fuels, I know plenty of sailors who protected traffic through the Persian Gulf choke point and personally saw soldiers protecting fuel convoys in Iraq who have a clear view of oil’s harmful effect on our—and their—safety.

Moreover, fighting climate change isn’t a zero-sum game between economy and environment. When we work to move towards 50 percent clean energy nationwide by the year 2030, we are creating the clean energy tech that will drive the next century just like oil did the last and getting the jump on our competitors around the world. And a bonus? Almost 10 percent of those employed in the solar industry in particular are U.S. veterans, finding an outlet for their technical and leadership skills after returning home.

But beyond these benefits, President Obama’s efforts to coordinate and lead the global fight against climate change should simply be a point of pride for the Democratic Party. At home, his EPA’s Clean Power Plan raised standards across the board while letting states choose how to meet their individualized targets. And abroad, his State Department secured not only the first bilateral climate deal ever with China, but also a truly global climate deal that creates a reporting structure to hold every country—rich and poor, large and small—accountable for showing progress on the world stage.

This election, voters will head to the polls juggling national security and economic issues alike. Climate change touches both of these policy areas and more, and it is time for Democratic candidates to press their advantage on this key national challenge. 2016 is a chance for every candidate who shares the values of security and prosperity to continue President Obama’s legacy of decisive, comprehensive action. Here’s hoping we hear that incredibly opportunity reflected on the debate stage next week.

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Jonathan Freeman is a fellow with the Truman National Security Project and a Ph.D. student in international relations at the London School of Economics. He has deployed twice to Iraq, once to Afghanistan, and is currently in the U.S. Army Reserves.

Photo: Participants are seen in silhouette as they look at a screen showing a world map with climate anomalies during the World Climate Change Conference 2015 (COP21) at Le Bourget, near Paris, France, December 8, 2015.  REUTERS/Stephane Mahe