Former President Donald Trump this week waded into a battle pitting governors against the Biden administration over the creation of a part-time element for the U.S. Space Force.

Speaking at the National Guard Association of the United States conference in Detroit, Mr. Trump on Monday vowed to create a Space National Guard if he returns to the White House for a second term.

“Now the Space Force is up and running, I agree with your leadership,” Mr. Trump told the crowd. “The time has come to create a Space National Guard as the primary combat reserve of the U.S. Space Force.”

---

---

National Guard Association President Frank McGinn applauded Mr. Trump’s support of a Space National Guard.

“I am grateful for President Trump’s pledge to establish a Space National Guard should he be elected for another term,” he said in a statement.

The NGAUS has maintained for several years that a Space National Guard is the ideal supplement for the Space Force, said Mr. McGinn, a retired two-star general in the Massachusetts Army National Guard.

The National Guard Association also invited Vice President Kamala Harris to address this year’s conference. Mr. Trump previously spoke to the NGAUS when he ran in 2016.

“Members of the National Guard are more than defenders of democracy; we’re all participants,” Mr. McGinn said. “We want to know how the next administration will support the National Guard and whether the Guard will continue its prominent role in the National Defense Strategy.”

The Biden administration doesn’t support the creation of a Space National Guard. It says it doesn’t make financial sense to create a separate organization to reinforce a small service like the Space Force.

The White House is pushing to shift Air National Guard units that carry out space missions directly into the Space Force. But that effort is opposed by the country’s governors.

“This legislation disregards gubernatorial authorities regarding the National Guard and undermines over 100 years of precedent as well as national security and military readiness,” the National Governors Association said in an April statement. “National Guard assets are critical components of states’ and territories’ responses to crises. Governors must maintain full authority as commanders in chief of these assets to protect operational readiness and America’s communities.”