The biggest threat facing the US, according to the first Democratic debate

Climate change. Nuclear weapons. China.

These were the most frequent answers offered by the 10 Democratic presidential candidates onstage at Wednesday night’s debate when asked to identify the “biggest threat” to the United States.

The moderator asked them to identify the biggest “geopolitical threat” — but many chose to identify what they see as the biggest existential threat. Climate change, for example, clearly poses a catastrophic risk to humanity above and beyond how it would alter geopolitical risks.

It’s perhaps no surprise that the candidates chose to interpret the question this way. Two of the threats they listed, climate change and nuclear weapons, had been coming up repeatedly in answer to the moderators’ previous questions. Earlier in the debate, Elizabeth Warren and Tulsi Gabbard emphasized the importance of “green energy” and a “green economy,” respectively. Tim Ryan, Beto O’Rourke, and Julián Castro mentioned renewables like solar energy and electric cars, and John Delaney talked about a carbon tax. Jay Inslee said fighting climate change would be his “top priority” as president.

Nuclear weapons had also been coming up earlier in the debate. Cory Booker, Gabbard, and Amy Klobuchar brought up the Iran nuclear agreement, and all three said President Trump was wrong to rip it up.

Many risk assessment experts would agree that climate change and nuclear warfare are among the top threats facing humanity. Another threat commonly cited by experts — advanced artificial intelligence — went undiscussed by the candidates, which was a bit surprising. Stephen Hawking once said, “The development of full artificial intelligence could spell the end of the human race,” and Elon Musk says it’s our “biggest existential threat.”

Here’s how each candidate answered, according to the transcript:

John Delaney: “The biggest challenge is China. The biggest geopolitical threat remains nuclear weapons.”

Jay Inslee: “The biggest threat is Donald Trump. No question about it.”

Tulsi Gabbard: “The greatest threat we face is that we are at greater risk of nuclear war.”

Amy Klobuchar: “Economic threat and China, but the major threat is what is going in the Mideast with Iran.”

Beto O’Rourke: “The existential threat is climate threat. We have to confront it before it’s too late.”

Elizabeth Warren: “Climate change.”

Cory Booker: “Nuclear proliferation and climate change.”

Julián Castro: “China and climate change.”

Tim Ryan: “China, without a question. They are wiping us economically.”

Bill de Blasio: “Russia, because they are trying to undermine our democracy and they are doing a damn good job of it and we need to stop them.”

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