By Donald Trump’s own admission, the push for a Space Force started as an offhand joke.

As regular readers know, the president said a year ago, in reference to a conversation he claims to have had with White House staff, “You know, I was saying it the other day, because we are doing a tremendous amount of work in space. I said, ‘Maybe we need a new force. We’ll call it Space Force.” And I was not really serious. Then I said. ‘What a great idea. Maybe we’ll have to do that.’”

In the months that followed, administration officials felt compelled to act on Trump’s not-really-serious idea, launching a major policy initiative intended to turn the Republican’s joke into a branch of the United States military.

Yesterday, as the New York Times reported, the president advanced the plan, though his Space Force has clearly taken a significant detour.

President Trump moved forward with his planned United States Space Force on Tuesday, signing an order to begin the process for establishing a new branch of the military that would be dedicated to handling threats in space. Mr. Trump’s directive orders the Defense Department to “marshal its space resources to deter and counter threats in space” – which the Pentagon already does. The newly created Space Force would be overseen by the Air Force, a concession to congressional critics who say the Pentagon does not need to add to its sprawling bureaucracy.

The fact that the Space Force will fall under the purview of the Air Force represents a retreat from Trump’s plan (to the extent that this White House actually has plans). As recently as five months ago, the administration insisted that the Space Force would be an entirely separate branch of the military.

“I’m hereby directing the Department of Defense and Pentagon to immediately begin the process necessary to establish a Space Force as the sixth branch of the armed forces,” the president declared last summer. “That’s a big statement. We are going to have the Air Force and we are going to have the Space Force – separate but equal. It is going to be something. So important.”

Trump’s “separate but equal” plan flopped in the face of widespread resistance. The new approach is something of a compromise: the White House will still get its Space Force, but it’ll be under the Air Force, which already has a Space Command.

The new approach will need congressional approval, which may prove difficult.

Even many conservatives have balked at this endeavor for months, and with a Democratic majority in the House, the initiative is likely to face quite a bit of skepticism on the Hill.