President Donald Trump on Monday ordered the Pentagon to create a new service branch dedicated to military operations in space.

“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,” Trump said at the White House, indicating that the proposed service would be completely separate from the other five existing services.

“We are going to have the Air Force and we are going to have a Space Force,” he said. “Separate but equal.”

Following Trump’s remarks, the White House separately issued a memorandum on space traffic, which did not mention Space Force.

Trump’s directive comes almost a year after the House passed its version of the fiscal 2018 defense authorization act, which would have required the Pentagon to establish a “Space Corps” but still within the Department of the Air Force. The provision was ultimately stripped out of the bill during negotiations with the Senate and replaced with a provision demanding a report from the Pentagon on the efficacy of a Space Corps.

Despite being commander in chief of the armed forces, Trump will need Congress’s help to establish a new space service.

“The president can’t create a new military service on his own,” said Todd Harrison, director of the aerospace security project at the Center for Strategic and International Studies. “There’s going to have to be legislation.”

Legislation would be necessary, for instance, to move authorities from existing service branches to Space Force. Currently, the Navy, Army and Air Force all conduct some space operations, which presumably would become Space Force’s responsibility. Space Force could also need legislation to create new positions and manpower policies for the service branch. And no Pentagon entity can operate without congressionally appropriated funding.

Role for Congress

Members of Congress from both parties who have been resistant to the Space Force idea from its conception spent Monday reminding the president that Space Force must first go through Capitol Hill before launching at the Pentagon.

“Establishing a service branch requires congressional action,” Rep. Michael R. Turner, who chairs the House Armed Services Subcommittee on Tactical Air and Land Forces, said in a statement. “We still don’t know what a Space Force would do, who is going to be in it, or how much is it going to cost.”

The Ohio Republican was the chief opponent of Space Corps last year in the House and was instrumental in demanding from the Pentagon a report on the need for a Space Corps.

“The congressionally mandated report evaluating a Space Force to answer those questions is due in August,” Turner said. “After we get the report that we required as a legislative body and the President signed off on, then this issue can be appropriately evaluated for what’s best for national security.”

Because Trump needs Congress to establish Space Force, his announcement effectively orders the Pentagon — which has pushed back on the Space Corps proposal at every turn — to draw up plans for the service.

“I don’t see how [the Defense Department] and how the Air Force is going to be able to continue to resist the creation of a Space Force,” Harrison said.

The House has already endorsed the Space Corps idea, making Trump’s announcement a coup for House Armed Services Strategic Forces Subcommittee Chairman Mike D. Rogers, the father of the Space Force concept.

“I am thrilled to have President Trump’s continued support for this critical mission to help strengthen our national security,” the Alabama Republican said. “I look forward to working with the President to make this initiative a reality.”

Watch: Department of Defense Briefing on Budget Cap Increase

Last redoubt?

If Trump’s desire to set up a Space Force can stifle resistance within the Pentagon, then only the Senate will stand between him and Space Force.

Florida Sen. Bill Nelson, who is up for re-election in November, and whose home state has six Air Force bases (plus NASA space launch facilities), already voiced his distaste for the idea on Twitter.

“The president told a U.S. general to create a new Space Force as 6th branch of military today, which generals tell me they don’t want,” Nelson, the top Democrat on the Armed Services Cybersecurity Subcommittee, tweeted Monday. “Thankfully the president can’t do it without Congress because now is NOT the time to rip the Air Force apart.”

Last year, Nelson and Arkansas Republican Tom Cotton offered an amendment to the Senate’s version of the defense authorization bill that would prohibit Space Corps from being funded.

According to Harrison, though, Trump’s announcement could help clear the way for Space Force in the Senate.

“I think a lot of that resistance has been backstopped by the Air Force,” Harrison said. “So now if the Air Force’s resistance is taken out of the equation because of what the president is directing, I’m not sure how much that resistance can hold in the Senate.”

Congress will almost certainly wait to act on Space Force until the Pentagon produces its report on the force. With the Senate wrapping up consideration on the fiscal 2019 defense authorization bill Monday evening, Space Force will likely again become an issue when Congress drafts the fiscal 2020 defense authorization bill.

For Harrison, Trump’s announcement could be enough to advance the proposal through Congress.

“I think this increases the odds of something happening significantly,” Harrison said. “It may be enough to tip the scales, to make this happen.”

John M. Donnelly contributed to this report.