Ramadi-retaking bogs down; Helmand situation deteriorating; What to watch in 2016; A few holiday #Longreads; and a bit more...

The battle to retake Ramadi is bogged down to skirmishes, occasional car bombs, sniper fire and tit-for-tat mortar exchanges between Islamic State fighters and Iraqi security forces. Baghdad’s troops still have not taken the government compound at the heart of the Anbar provincial capital, but an Iraqi general told Agence France-Presse they made some modest gains in their advance Tuesday, and are currently “on the edge of the government district,” the New York Times reports.

ISIS fighters had destroyed three bridges into Ramadi, but U.S.-provided portable bridges restored that route, spokesman for the U.S.-led coalition, U.S. Army Col. Steve Warren said Tuesday.

Warren: “I think the fall of Ramadi is inevitable…That said, it’s going to be a tough fight.”

Thousands of civilians are believed to remain in the city, where Baghdad’s forces are still “finding huge amounts of ammunition and explosives, including rockets made from gas canisters.”

Warren also said that coalition forces had recovered ISIS leaflets in the nearby city of Fallujah urging its fighters — if they lose control of the city — to impersonate Iraqi security forces and commit atrocities. But the Times adds, “The authenticity of the leaflets could not be independently confirmed, and experts on the Islamic State were debating their validity after the coalition publicized them on Tuesday.” Such pushback was immediately apparent after Warren tweeted out the leaflet, which you can glimpse, along with the pushback, here.

And don’t miss this on-the-ground take from U.S. Marine trainers building up Camp Manion—roughly 25 miles from Ramadi—in al-Taqqadum, Iraq, from the Washington Post’s Thomas Gibbons-Neff.

Should the U.S. stop being so cautious about not killing civilians in its airstrikes over Syria and Iraq? It’s been a question that has increasingly bedeviled the White House, as WaPo’s Karen DeYoung and Missy Ryan report. “While much of the push for increased flexibility has come from the State Department rather than the military, a senior administration official said, “nobody’s advocating for completely loose rules.”

According to new Pentagon figures released Tuesday, “about 56 percent of all coalition aircraft return from ‘strike missions’ without having used their weapons, either because of bad weather or a judgment that the risk of civilian casualties is too high. That compares with estimates as high as 75 percent just a few months ago.”

For its part, “The Pentagon has acknowledged at least two incidents in which it says some civilians were killed by coalition airstrikes, which began in Syria more than 15 months ago. It says a about a dozen allegations are still being examined, including an early-December bombing raid in the northeastern Syrian village of al-Khan in which between 26 and 39 civilians were reportedly killed.”

The bottom line, according to one U.S. official: “This is not a new debate. Anytime you’re in an armed conflict, at some point or another, usually at many points, there is going to be a renewed discussion about rules of engagement.” More here.

Russia now faces allegations it has killed hundreds of civilians in its airstrike campaign over Syria, according to a new report from the human rights group Amnesty International. That, here.

Meantime, U.S.-made TOW anti-tank missile systems just showed up in the hands of fighters from the al-Qaeda-linked Turkistan Islamic Party, Long War Journal reports. “If the missile was operated by an FSA [Free Syrian Army] group, this would offer more evidence that TOW-supplied rebel groups continue to support jihadist operations in the country.” More, here.

Kabul has rushed troops to the deeply troubled Helmand district of Sangin. A dire scene played out in the southern province over the weekend as Taliban fighters seized the district center and government buildings while surviving Afghan security forces grew increasingly isolated without food or ammo. “All but two of Helmand's 14 districts are effectively controlled or heavily contested by Taliban insurgents,” AFP reports.

More than a year after pulling out the province, the Brits just sent a “tiny but symbolic” element of 10 troops back to Helmand, the Ministry of Defense said Monday. “The 10 British troops, part of a 300-strong Nato force, are based at Camp Shorabak, about 50 miles (80km) from Sangin. The MoD said they would remain inside the camp providing advice and infantry training and would not be involved in combat.”

For what it’s worth: “A US military source was quoted on Monday saying US special forces were also supporting Afghan forces in Sangin and that a British SAS unit was working alongside them.” The Guardian has that, here.

The names of the six U.S. troops killed in Monday’s suicide bombing near Bagram Air Base—the deadliest attack on American troops there since 2013—have been released. They include “a family man from Long Island, New York; a South Texan; a New York City police detective; a Georgia high school and college athlete; an expectant father from Philadelphia; and a major from suburban Minneapolis with ties to the military's LGBT community.” The Associated Press has the somber details, here.

What to watch in 2016. Keep an eye on these nine story lines in warfighting, industry, politics, and technology. Defense One’s crack squad — Molly O'Toole, Patrick Tucker and Marcus Weisgerber — lay them out, here.

From Defense One

What’s the next big weapon? Instigating social protest movements. Governments and non-state actors will increasingly foment citizen protests — think the Arab Spring, Ukraine’s Euromaidan Revolution, Hong Kong’s Occupy Central — to topple terrorist states and influence regimes. “Russian military theorists were the first to openly discuss this shift in the art of war—and to accuse America of pioneering techniques of fomenting viral protests abroad.” Quartz’ Micah White makes the argument, here.

“Call of Jihad”: Watch this Quartz video to see just how closely ISIS is mimicking Western pop culture — video games and Hollywood movies — to produce slick and violent recruiting videos that draw new recruits. Video here.

Pakistan’s race to build tiny nukes is going to backfire. Islamabad's tactical nuclear weapons don't look so fun for any Pakistani who thinks through the math. Quartz’s C. Christine Fair lays it out, here.

Obama says his ISIS strategy is working better than his attempts to explain it. In the wake of the president’s recent press conferences, The Atlantic’s David A. Graham wonders: just how important is messaging, and can it really be blamed for subpar policy results? That, here.

Welcome to the Christmas Eve-Eve edition of The D Brief, from Ben Watson and Bradley Peniston. Tell your friends to subscribe here: http://get.defenseone.com/d-brief/. Want to see something different? Got news? Let us know: the-d-brief@defenseone.com.

The U.S. Army would like you to know that it has no plans to transport troops into combat aboard unmanned helicopters. Cargo delivery remains the top priority for the project, the army’s capability manager for unmanned aircraft systems, Col. Paul Cravey, told Flightglobal.

See also this take on the Army’s pursuit of an unmanned Black Hawk, which passed a key test in the fall, from our own Patrick Tucker.

And now for something completely different: China reportedly tested an ICBM launched from a railroad car. More on that, here.

Your holiday break #LongReads. No. 1 comes from former State and DoD official Greg Archetto whose take as an “arms dealer with a conscience” spans Libya, Yemen, Syria, Rand Paul and why it all led him to “quit the Pentagon.” It’s a bit of a take-no-prisoners retrospective, and you can read it in full over at SOFRep.com, here.

No. 2: Deterrence doesn’t work in cyberspace. That’s the conclusion of New America’s Peter W. Singer, author of the invaluable “Cybersecurity and Cyberwar”: “There is perhaps no national security problem more 21st century in both its definition and form than cybersecurity. And yet to solve it, the ready solution in nearly every U.S. national security conversation today is that tried and true 20th-century framework of deterrence.” Singer explains why, and what to do about it, here.

Lastly this year—fake news alert—“ The National Security Agency routinely intercepts children’s letters to Santa, internal agency documents have revealed,” the satirical site DuffelBlog writes. “The NSA is prohibited from directly monitoring American citizens under both Executive Order 12333 and the Foreign Intelligence Surveillance Act. However, because the letters are addressed to the North Pole, which falls outside of U.S. territory, they are considered potential foreign intelligence signals which the NSA is authorized to intercept.” Read the rest of that straight-faced delivery just in time for the holidays, here. And we’ll see all you again on Jan. 4. Have a great New Year, gang.