Vice President Pence arrives to speak at an event in the Rose Garden of the White House on May 3, 2018. (Jabin Botsford/Washington Post)

Vice President Mike Pence laid out an ambitious plan Thursday that would create a military command dedicated to space this year and eventually establish a “Space Force” as the sixth branch of the U.S. military.

In a speech at the Pentagon, Pence warned of the advancements that potential adversaries were making and issued what amounted to a call to arms to preserve the military’s dominance in space.

“Just as we’ve done in ages past, the United Statesl meet the emerging threats on this new battlefield,” he said. “The time has come to establish the United States Space Force.”

The creation of a new branch of the military – the first since the Air Force was created in the wake of World War II in 1947 – could require a significant reorganization of the Pentagon. And some officials within the military and national security communities fiercely oppose the idea. The Air Force in particular might lose key responsibilities. The proposal would also need Congressional approval.

In the meantime, White House officials have been working with national security leaders to aggressively move ahead without Congress. The first step would be to create a U.S. Space Command by the end of the year, a new combatant command that would have dedicated resources, be led by a four-star general, and be tasked with defending space, the way the Pentagon’s Pacific Command oversees the ocean.

The Pentagon will also begin pulling space experts from across the military and setting up a separate acquisitions office, dedicated to buying satellites and developing new technology to help it win wars in space.

For months, President Trump has been calling a Space Force, a new, free-standing military department, with its own chain of command and uniforms. The White House intends to work with lawmakers in submitting legislation by early next year, a senior administration official said, with the hopes of standing up the department as early as 2020.

In his speech, Pence acknowledged the difficulties in standing up a new service, and said the Pentagon would create an Assistant Secretary of Defense for Space, a new top level civilian position reporting to the Secretary of Defense “to oversee the growth and expansion of the sixth branch of service.”

The new command and reorganization “should be budget neutral,” Scott Pace, the executive secretary of the National Space Council, said in an interview. “However, going forward there probably will need to be an increase in resources to buy improved capabilities and more warfighters as the Space Force matures.”

The creation of a Space Force has met with opposition, inside and out of the Pentagon. Defense Secretary Jim Mattis said in a memo last year to Sen. John McCain, R-Ariz., that he opposed “the creation of a new military service and additional organizational layers at a time when we are focused on reducing overhead and integrating joint warfighting functions.”

While not endorsing a full-fledged service branch, Mattis told reporters earlier this week that military leaders “are in complete alignment with the president’s concern about protecting our assets in space to contribute to our security to our economy and we’re going to have to address it as other countries show a capability to attack those assets.”

Paul Scharre, a senior fellow at the Center for a New American Security, called a Space Force “a dumb idea,” in an commentary on Defense One, which first reported some of the details of the plan. While Scharre agreed that “space is the American Achilles heel,” he said creating a new bureaucracy with a single focus would handicap the military: “The United States needs to focus on the mission, not the domain.”

For years, some members of Congress and military leaders have been warning that space is no longer a peaceful sanctuary, but a war fighting domain that needs more attention and resources. Space is vital to the way the United States wages war; The Pentagon’s satellites are used for missile-defense warnings, guiding precision munitions, and providing communications and reconnaissance.

Russian and China have made significant advancements, challenging the United States’ assets in space.

In 2007, China blew up a dead weather satellite with a missile, creating a massive debris cloud in orbit. It also demonstrated the ability to hit satellites in a much deeper orbit where the military parks some of its most sensitive assets.

Pence cited adversaries’ advancements in developing hypersonic missiles, which can travel up to five miles per second and evade missile warning systems.

“America will always seek peace, in space as on earth,” Pence said. “But history proves that peace only comes through strength. And in the realm of outer space, the United States Space Force will be that strength.”