Trump to send National Guard to southern border President Donald Trump on Wednesday said he would send National Guard units to secure the border with Mexico while plans for his proposed wall work their way through Congress.

WASHINGTON — President Donald Trump is ordering U.S. troops to the southern U.S. border, but the move does not appear to be as unusual as the White House first billed it this week.

The Pentagon and White House on Wednesday walked back President Donald Trump promise to handle border security “militarily,” saying the proposed moves will be restricted to National Guard personnel and be similar to past operations in Southern states.

Department of Homeland Security Secretary Kirstjen Nielsen said Wednesday at a White House press conference that her agency and the Pentagon are coordinating with governors on the specifics of the deployments, with exact numbers and missions to be announced later. Guardsmen will serve in support roles, and not actual law enforcement activities.

The announcement came roughly 24 hours after Trump announced at a similar event that “we’re going to be guarding our border with the military,” adding “we really haven’t done that before.”

As many as 11,800 military families face deportation issues, group says While the active duty members themselves are protected — because in order to enlist a service member has to show proof that they are in the country legally — their undocumented spouses are not.

The comments drew questions and concerns about the commander in chief overstepping traditional military limits.

“A lot of folks were envisioning a line of active-duty troops and tanks on the border after Trump’s first comments,” said Todd Weiler, a former senior Pentagon official during Obama’s tenure.

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“What we’ll probably end up seeing is some vehicles and aerial assets supporting the border patrol, which is normal.”

Weiler credited Defense Secretary Jim Mattis — who was silent beside Trump when he made his Tuesday comments — for helping “calm” the situation

“It’s good that we have folks in the Pentagon who are quick to react and use the ‘what the president meant to say’ line,” he said.

In recent days, Trump has floated the idea of having the military pay for a controversial border wall with part of its $700 billion fiscal 2018 defense budget, a suggestion that raised similar problematic issues of military readiness and responsibilities.

Nielsen on Wednesday emphasized the deployments would be similar to actions taken under former presidents Barack Obama and George W. Bush. Duties will include aerial surveillance work and infrastructure support.

She said she anticipates the moves will happen as soon as possible.

A member of the National Guard checks on his colleague inside a Border Patrol Skybox near the Hidalgo International Bridge in Texas in April 2011. White House officials on Wednesday said they hope to conduct similar National Guard border security support missions in coming weeks. (Delcia Lopez/AP)

If the Guard is deployed as it has been in the past, there would be little those troops could do to stop crime along the border, said William Banks, author of “Soldiers on the Home Front: The Domestic Role of the American Military” and director at the Institute for National Security and Counterterrorism at Syracuse University’s College of Law.

The Posse Comitatus Act prevents the federal government from using federal troops to conduct local law enforcement on U.S. soil. Banks called it the backbone of colonists’ grievances when the United States declared independence from England.

“The phrase is known by every Private 1st Class in the U.S. military,” Banks said.

It’s also why National Guard forces are under state control, Banks said. The president could federalize the National Guard in an extreme situation, such as when Bush requested that the Guard forces responding to Hurricane Katrina be placed under federal control.

But even then, guardsmen would not have the authority to participate in law enforcement, such as preventing an illegal crossing or conducting a drug interdiction, he said.

There are exceptions, Banks said. Title 32 of the Code of Federal Regulations, section 185.4 provides National Guard troops “immediate response authority” — the ability to defend themselves if they are under immediate threat.

There is also a broader, short-term “emergency authority,” which allows the forces to take control “in extraordinary emergency circumstances where prior authorization by the president is impossible and duly constituted local authorities are unable to control the situation, to engage temporarily in activities that are necessary to quell large-scale, unexpected civil disturbances.”

Nielsen said none of those issues are under consideration at the moment. Federal departments are coordinating with all of the border state governors on the steps ahead, and administration officials are optimistic they will have full support from local leaders.

“Border security is homeland security, which is national security,” she said. “It’s not a partisan issue. It’s not something we can separate out. It’s core to being a sovereign nation.”

California officials have already publicly expressed resistance to the plan.

Trump has said he’s turning to the military for help with immigration enforcement because of congressional Democrats’ opposition to funding his proposed border wall. That issue is unlikely to be resolved in coming months, given the current fractured political environment on Capitol Hill.