The Trump administration published its National Security Strategy today (Dec. 18), omitting climate change entirely. In contrast, climate change was listed as one of eight national security threats to the US in former president Obama’s strategy, last published in 2015.

The term “climate change” was used 13 times in Obama’s 2015 document; it doesn’t appear once in the new version. The only oblique mention of “climate” as it pertains to the environment comes on page 22 (pdf), in a section titled “Embrace Energy Dominance”:

Climate policies will continue to shape the global energy system. US leadership is indispensable to countering an anti-growth energy agenda that is detrimental to US economic and energy security interests. Given future global energy demand, much of the developing world will require fossil fuels, as well as other forms of energy, to power their economies and lift their people out of poverty. The United States will continue to advance an approach that balances energy security, economic development, and environmental protection. The United States will remain a global leader in reducing traditional pollution, as well as greenhouse gases, while expanding our economy. This achievement, which can serve as a model to other countries, flows from innovation, technology breakthroughs, and energy efficiency gains, not from onerous regulation.

The omission comes less than a week after Trump signed the National Defense Authorization Act, which sets policy for the US military for the coming fiscal year. That bill included a large section on climate change, in which current and former top US military brass stated the threat it poses to national security. Secretary of defense James Mattis was quoted in the bill saying the consequences of climate change “impact our security situation.” By signing the defense bill, Trump also ordered a report on “vulnerabilities to military installations” that climate change could cause in the next 20 years.

The difference in substance and tone between the defense bill and the security strategy document may be explained by the fact that the former originated in Congress while the latter came straight from the Trump administration.

The climate change section of the defense bill was added by a Democratic representative and was challenged by a Republican representative, but the challenge was ultimately defeated in a House vote. That means several Republicans decided that the climate provisions should remain, according to the legal blog LawFare. The National Security Strategy, in contrast, was originated in the White House. It’s possible that the gulf in thinking between the two documents signals a growing divide between Republicans in Congress—among whom discussion of climate change as a threat is becoming more common—and the Trump administration.