Back in March, President Donald Trump first decreed his hope for an American “Space Force” — a branch of the army dedicated to military matters in space. But is that even legal?

On episode 6 of I Need My Space, I asked space lawyer Michael Listner for the details on whether or not Trump’s plan could land the states in legal trouble.

The basic answer? There is none. It’s complicated.

Judging the legality of Space Force comes down to an old, but still important document, called The Outer Space Treaty, which went into effect in 1967. It’s a critically important document for space law. It essentially says that space belongs to no one nation or private company or individual. It’s intentionally vague, according to Listner, and that’s where everything gets complicated.

According to Listner, President Eisenhower first came up with the idea after World War II. “Back in the 1950s, President Eisenhower was very concerned about another Pearl Harbor happening in outer space,” Listner explained. “[Eisenhower] was concerned [space] was going to become a new colonial battleground where nations would try to lay claim on certain portions of space, so he proposed the Outer Space Treaty, which is based a lot on the Antarctic Treaty of 1959.”

“No,” Listner tells me, when I ask if Space Force violates the Outer Space Treaty. “[But] it depends what the mission of the space force is. I really detest the term ‘war in space’ because this isn’t a science fiction movie — I mean, we recently recognized space as a domain or a theater of war. But we’re not fighting for territory in outer space.”

“It’s really ambiguous and fluffy,” he says. “One obligation is ‘You can’t place a nuclear weapon in outer space’. Now, what is ‘space’? We can talk hours about the legalities of where space is, because there is no internationally recognized definition about where the atmosphere ends and space begins. Even though any weapon of mass destruction is prohibited from being placed in space, it doesn’t prohibit military activity so long as it’s for ‘peaceful purposes.’”

This raises some important questions, especially considering Trump’s speech back in March didn’t sound so “peaceful.”

“My new national strategy for space recognizes that space is a war-fighting domain, just like the land, air, and sea,” the president told a crowd of military members in San Diego, California. “We might even have a space force … develop another one.”

Perhaps the only way to really understand the legality of a space force is to update the Outer Space Treaty. Listner says he thinks the document is “of another time,” and that it was created for Cold War issues. Perhaps it’s due for some revisions.

Let’s just hope the ambiguity gets cleared up before we are in need of some real-life Jedis.

Check out more from the conversation with Michael Listner in the sixth episode of I Need My Space. It’d mean the world to us if you subscribed, rated, and reviewed the show.