Happy Friday and welcome to Overnight Defense. I'm Ellen Mitchell, and here's your nightly guide to the latest developments at the Pentagon, on Capitol Hill and beyond. CLICK HERE to subscribe to the newsletter.

THE TOPLINE: Acting Defense Secretary Patrick Shanahan Patrick Michael ShanahanHouse Armed Services chairman expresses confidence in Esper amid aircraft carrier coronavirus crisis Boeing pleads for bailout under weight of coronavirus, 737 fallout Esper's chief of staff to depart at end of January MORE on Friday is expected to approve a new policy that would ease restrictions on troops interacting with migrants entering the country, a move that would expand the military's activities at the U.S.–Mexico border, The Washington Post reported.

Shanahan will reportedly sign off on a request from the Department of Homeland Security to allow military lawyers, cooks and drivers to help with handling migrants entering the United States.

What the waiver would do: Senior Defense Department officials recommended that Shanahan approve the request, which would require authorizing waivers for about 300 troops, the Post reported. A 2006 policy currently prohibits military personnel from coming into contact with migrants.

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The Pentagon has approved one request since October to waive the restrictions on interactions, allowing troops to provide emergency medical care to migrants.

Increasing responsibilities: The waiver would come after the Pentagon this month approved a March request from the Department of Health and Human Services to find housing for as many as 5,000 unaccompanied migrant children. The Defense Department would not oversee the housing of the children.

Asked last week whether he could rule out that U.S. troops will be involved in the detention of migrants, Shanahan said, "We don't do law enforcement."

Troop numbers now: There are now roughly 3,000 active-duty service members at the southern border after Trump first deployed troops last year to assist in addressing a migrant caravan traveling to the United States from Central America.

Those troops are in addition to about 2,000 National Guard members who were deployed in April 2018 to assist in border security.

TRUMP TELLS NRA HE'S PULLING U.S. OUT OF ARMS TREATY: President Trump Donald John TrumpBiden on Trump's refusal to commit to peaceful transfer of power: 'What country are we in?' Romney: 'Unthinkable and unacceptable' to not commit to peaceful transition of power Two Louisville police officers shot amid Breonna Taylor grand jury protests MORE on Friday announced he is withdrawing U.S. support for an international arms-trade treaty, the administration's latest move to distance the country from global agreements and institutions.

Speaking at a National Rifle Association (NRA) convention in Indianapolis, Trump said he would "never" ratify the United Nations Arms Trade Treaty that was signed by former President Obama in 2013.

"Under my administration, we will never surrender American sovereignty to anyone," Trump told the group, which erupted in applause. "We will never allow foreign bureaucrats to trample on your Second Amendment freedoms."

Trump signed paperwork instructing the Senate to halt the ratification process, held up the document as the crowd cheered "USA, USA," then tossed his pen into the crowd.

A senior administration official later told reporters that a formal withdrawal letter would be submitted to the U.N. "in the coming days."

What the treaty does: The treaty is designed to regulate the $70 billion international arms trade and prevent conventional arms being used by terrorists, human traffickers and others. It was submitted to the Senate by the Obama administration in 2016 but was never ratified.

Roughly 100 other countries have signed and ratified the treaty and more than two dozen others have signed but not ratified it.

Why Trump opposes it: Critics of the treaty, including the NRA and other conservative groups, said it would have infringed on national sovereignty, an argument rejected by the Obama administration.

The Trump administration was also worried the U.S. would be held to an unfair standard because the world's second- and third-largest arms exporters, Russia and China, are not parties to the treaty. The U.S. is the world's No. 1 exporter of arms.

"The U.S. already has significant controls in place to regulate our arms transfers. Other countries do not," the senior administration official said.

Lawmakers hit back: Sen. Bob Menendez Robert (Bob) MenendezKasie Hunt to host lead-in show for MSNBC's 'Morning Joe' Senators ask for removal of tariffs on EU food, wine, spirits: report VOA visa decision could hobble Venezuela coverage MORE (N.J.), the Foreign Relations Committee's ranking Democrat, said the U.S. withdrawal would "turn back the clock on the little progress we have made to prevent illicit arms transfers" and was done only because of "Republicans' paralyzing fear of backlash from the NRA."

"The president's action today is yet another mistaken step that threatens to make the world less safe, rather than more secure," said Thomas Countryman, a former State Department official who was Obama's lead negotiator for the treaty. "It is sad, but to be expected, that this president opposes efforts to require other countries to meet the high standards of U.S. military export decisions."

WARREN OFFERS PLAN TO IMPROVE MILITARY HOUSING: Sen. Elizabeth Warren Elizabeth WarrenDimon: Wealth tax 'almost impossible to do' CNN's Don Lemon: 'Blow up the entire system' remark taken out of context Democrats shoot down talk of expanding Supreme Court MORE (D-Mass.) on Friday unveiled a plan to address widespread issues in military housing run by private contractors, underscoring her efforts to promote new ideas and policies in her campaign for the White House.

Warren, who has been notable in the race for the Democratic presidential nomination for outlining policy goals, discussed the plan in a Medium post shared by her campaign press office.

It was also unveiled as a Senate bill co-sponsored by three fellow members of the Senate Armed Services Committee, Sens. Richard Blumenthal (D-Conn.), Martin Heinrich Martin Trevor HeinrichSenate Democrats demand White House fire controversial head of public lands agency Senate Democrats seek removal of controversial public lands head after nomination withdrawal Five takeaways from final Senate Intel Russia report MORE (D-N.M.) and Kirsten Gillibrand Kirsten GillibrandSunday shows preview: Justice Ginsburg dies, sparking partisan battle over vacancy before election Suburban moms are going to decide the 2020 election Jon Stewart urges Congress to help veterans exposed to burn pits MORE (D-N.Y.), who is also running for president.

"Today I'm rolling out a plan to improve our military housing, protect families from abuse, and hold private developers accountable for the promises they make to those who serve our country," Warren wrote in the post.

The background: A 2018 Reuters investigation followed by a series of congressional hearings have unveiled deplorable living conditions in military housing, including black mold, rodent infestations and collapsing ceilings.

The issue has prompted bipartisan outrage, with lawmakers vowing to address it in this year's annual defense policy bill.

The Pentagon has also proposed some solutions, including a tenant bill of rights that would allow tenants to withhold rent and move at no cost if repairs aren't made.

Warren's plan: Warren's plan, too, includes a tenant bill of rights.

In addition, the bill would mandate regular and unannounced inspections of the housing by independent, certified inspectors.

The plan would also establish a resident survey, public database of complaints and an annual report on housing conditions.

The Pentagon would also have to publish the details of housing contracts in the Federal Register and require that each landlord annually submit to the Pentagon financial statements that would then be made public.

It would also mandate that leases be standardized across the Defense Department and would require the Defense secretary to establish formal written guidance for entering into and renewing contracts, including the ability to withhold payment or rescind a contract if a housing provider breaches the terms.

The bill would also cover medical costs of anyone with health issues caused by the unsafe housing conditions.

ON TAP FOR MONDAY

Marine Corps Commandant Gen. Robert Neller, Navy Chief of Naval Operations Adm. John M. Richardson, Air Force Secretary Heather Wilson, Air Force Space Command Vice Commander Lt. Gen. David Thompson, Rep. Seth Moulton Seth MoultonThe Hill's Morning Report - Presented by Facebook - Markey defeats Kennedy; Trump lauds America's enforcers in Wisconsin Moulton fends off primary challenges in Massachusetts Portland: The Pentagon should step up or pipe down MORE (D-Mass.), and State Department Policy Planning Director Kiron Skinner will speak at New America's annual Future Security Forum beginning at 8:30 a.m. at the Ronald Reagan Building in Washington, D.C.

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