That did it.

It’s official. James “Mad Dog” Mattis is my favorite member of Donald J. Trump’s Cabinet.

The secretary of defense has spoken in direct contradiction to the head of the Environmental Protection Agency and the president of the United States by declaring — be sure you’re sitting down — that climate change is real and it presents a threat to our national security.

Who would have thought that a retired Marine general with the nickname of “Mad Dog” would emerge as the premier grownup in the new president’s Cabinet.

Here’s part of what Mattis said, according to the Huffington Post: “Climate change is impacting stability in areas of the world where our troops are operating today,” Mattis said in written answers to questions posed after the public hearing by Democratic members of the committee. “It is appropriate for the Combatant Commands to incorporate drivers of instability that impact the security environment in their areas into their planning.”

Trump has said climate change is a hoax perpetrated by “the Chinese.” The EPA administrator, Scott Pruitt, has sued the EPA more than a dozen times and has called for its elimination. He has expressed openly his belief that climate change is not real, joining a paltry list of climate change deniers.

Now we have a defense secretary making sense. He calls climate change a national threat. His remarks well might reveal fissures within the Trump administration. As the Huffington Post reports: “These remarks and others in the replies to senators could be a fresh indication of divisions or uncertainty within President Donald Trump’s administration over how to balance the president’s desire to keep campaign pledges to kill Obama-era climate policies with the need to engage constructively with allies for whom climate has become a vital security issue.”

Semper fi, Gen. Mattis.