On Tuesday, Elon Musk took his furthest public step into the whirlpool of controversial decisions made by President Donald Trump, when the SpaceX and Tesla chief said Rex Tillerson, ex-CEO of ExxonMobil and Trump’s nominee for Secretary of State, “has the potential to be excellent” in the position.

Musk, the world’s most visible proponent of electric propulsion, added that the sort-of endorsement “may sound surprising coming from me.”

The comments took place on Twitter, where Musk replied to a favorable op-ed in The Economist endorsing Tillerson for the job of America’s foreign affairs chief.

Tillerson was approved Monday by the Senate Foreign Relations Committee vetting him for Secretary of State, and will likely be confirmed by the full Senate next week.

So why would Musk endorse Tillerson? There were a number of theories floating around online Tuesday, but what we know is that Musk has had several meetings with Trump and his top advisors, and will serve on the president’s Strategy and Policy forum.

Musk also praised Tillerson, who acknowledged that climate change was affected by human actions while testifying before Congress in 2010, but that he did not know “to what extent [it is caused by humans] and therefore what can you do about it.” Musk is well aware of the extent of human-caused climate change, which is why he knew his opinion would be surprising.

When asked to expand on his endorsement, Musk replied to a reporter on Twitter: “Rex is an exceptionally competent executive, understands geopolitics and knows how to win for his team. His team is now the USA.”

Musk finished his appraisal of Tillerson by urging us to give Tillerson the benefit of the doubt, “unless his actions prove otherwise.”

That caveat gives Musk some wiggle room, especially if Tillerson uses his position as the second-most important diplomat in the executive branch (next to the President) to pursue the corporate-friendly, climate change-denying agenda of his boss.

Later Tuesday evening, Musk hopped back on Twitter to defend Tillerson to the commenters who quickly pointed out Tillerson’s not-so-stellar record on climate change. Musk quoted Tillerson, who said at his Senate confirmation hearing: “I think it’s important that the United States maintain its seat at the table in the conversation on how to address threats of climate change. They do require a global response.”

Musk followed up with this as well:

That’s a nice sentiment, but Tillerson’s boss has been wildly inconsistent on what that global response should be, at one point threatening to pull the U.S. out of the Paris Accords, then saying he had an open mind about participating in the multinational push to reduce carbon emissions. It’s pretty strange that Musk would take Tillerson saying the “risk of climate change does exist” as a plus, when the prospective Secretary of State is basically implying that climate change is just a risk, and not a wildly dangerous global crisis that is already happening.

Musk also addressed (with plenty of humor), Tillerson’s not-so-funny ties to Russian President Vladimir Putin.

Sure, it’s difficult to refuse a medal from Putin, but it’s also tough to turn down a multibillion-dollar deal with major Russian oil company Rosneft, like the one Tillerson negotiated in 2011.

Musk ended the night on a resigned note.

You and me both, buddy.

Photos via Getty Images / Drew Angerer