On Friday, the Obama administration put climate change on the par with other global challenges like cybersecurity, terrorism, and Russian aggression, warning in a 35-page national-security memo that climate change poses “an urgent and growing threat to our national security.”

Republicans are sure to criticize this memo, just like they criticize Obama's failure to lead on foreign crises. And yet, even George W. Bush’s administration admitted that climate change is a problem for the military. Thomas Fingar, who chaired Bush’s National Intelligence Council, said in 2008, “We judge global climate change will have wide-ranging implications for U.S. national security interests over the next 20 years ... We judge that the most significant impact for the United States will be indirect and result from climate-driven effects on many other countries and their potential to seriously affect U.S. national security interests." Just last fall, the Pentagon released a landmark roadmap on climate change that found it to be a “threat multiplier” with the potential “to exacerbate many of the challenges we already confront today—from infectious disease to armed insurgencies.” 

But Republicans remain unconvinced that climate change is caused by humans or a serious threat to the plan, so they're not likely to accept that climate change is a national security issue, too. But in 2016, when the GOP nominee elaborates his or her (OK, his) plans for military preparedness, he's going to find this issue hard to avoid. He'll need to at least acknowledge the challenges that rising seas and temperatures pose to U.S. interests abroad, including military infrastructure and operations.

Otherwise he'll be struck dumb when Hillary Clinton makes it a campaign issue: Last fall, the former secretary of state said climate change is "the most consequential, urgent, sweeping collection of challenges we face as a nation and a world.”