DHS’ Nielsen quits; US troops leave Libya; ICC prosecutor barred; Russia tests missile; And a bit more.

DHS Sec. Nielsen resigns in two-page letter to POTUS. After 16 months on the job, Kirstjen Nielsen tendered her resignation Sunday evening after meeting with President Donald Trump at the White House.

Context: “Ms. Nielsen had been blindsided by Mr. Trump’s sudden decision to drop the nomination of Ron Vitiello, a veteran border official, from consideration to head U.S. Immigration and Customs Enforcement,” The Wall Street Journal reports. Nielsen’s decision also comes “amid a surge in the number of migrants at the border with Mexico,” Reuters reports. A senior admin official also told Reuters that Trump asked for Nielsen’s resignation and she complied. The Associated Press, by contrast, reported Nielsen “went into the White House on Sunday to meet with Trump not knowing whether she’d be fired or would resign. She ended up resigning, though she was not forced to do so.”

Bottom line up front: “The development Sunday was unexpected,” AP writes. She’ll stay on the job until Wednesday, Nielsen said in a tweet later Sunday evening.

Worth noting: “Her departure had been repeatedly rumored over the past year,” Reutes writes, “particularly after a wave of anger over the administration’s 2018 family separation policy at the border with Mexico and most recently as U.S. border officials estimated that 100,000 migrants were apprehended at the southern border in March, the highest level in a decade.”

The new acting head of DHS will be Kevin McAleenan, commissioner of the U.S. Customs and Border Protection, Trump announced in a tweet Sunday evening. "McAleenan is a longtime border official who is well-respected by members of Congress and within the administration," AP writes.

That makes four vacancies in the president’s cabinet:

• DHS secretary (acting as of Thursday: McAleenan)
• Pentagon chief (acting: Patrick Shanahan)
• Interior secretary (acting: David Bernhardt)
• White House chief of staff (acting: Mick Mulvaney)

Nielsen’s legacy is uneven, AP writes. Presently, “migrants seeking asylum are waiting in Mexico as their cases progress. She also moved to abandon longstanding regulations that dictate how long children are allowed to be held in immigration detention, and requested bed space from the U.S. military for some 12,000 people in an effort to detain all families who cross the border. Right now there is space for about 3,000 families, and facilities are at capacity.”

Here are 19 key White House departures, in one graphic by Agence France-Presse.

What now? Standby, folks. “A press conference to announce the most recent border numbers [for March] — scheduled to be held by McAleenan on Monday — was postponed,” AP writes. And after all the news broke Sunday evening, Trump tweeted his intentions, writing, “Will Close Southern Border If necessary......Mexico must apprehend all illegals and not let them make the long march up to the United States, or we will have no other choice than to Close the Border and/or institute Tariffs. Our Country is FULL!”

From Defense One

America, You're Not Listening to Us // Anatoly Antonov: Russia’s ambassador: We’re ready for urgently needed security dialogue — when our U.S. counterparts are ready to engage in good faith.

The False Promises of Trump’s Arms Sales // A. Trevor Thrall and Jordan Cohen: U.S. export deals are undermining regional stability and sending jobs abroad.

Yemen Cannot Afford to Wait // Robert Malley and Stephen Pomper: The scars in the country run deep—and the U.S. shares responsibility.

Staffing Shortages Impede State Department Monitoring of War-Zone Contracts // Charles S. Clark, Government Executive: Watchdog finds several bureaus allowed questionable invoices to go through.

Welcome to this Monday edition of The D Brief by Ben Watson. Thanks for reading! And if you’re not subscribed, you can do that here. On this day 10 years ago, U.S. officials told reporters “cyberspies [had] penetrated the U.S. electrical grid and left behind software programs that could be used to disrupt the system.” Word of the breaches came one week before the Obama administration's first cybersecurity review.

The U.S. and the UN want Libya’s Khalifa Haftar to stop his offensive to Tripoli, which “risks a full-blown civil war,” and has contributed to the deaths of nearly three-dozen people and 50 wounded others, AFP and Reuters report from the Libyan capital city.
What’s going on: “Haftar's forces and the UN-backed unity government exchanged air strikes Sunday, three days after Haftar launched an offensive to seize the capital,” AFP writes.
On one side is Haftar — a former officer in Gaddafi’s army — and his eastern Libyan National Army, or LNA. On the other is the government of Prime Minister Fayez al-Serraj and his Government of National Accord, or GNA. Al-Serraj "comes from a wealthy business family, [and] has run the Tripoli government since 2016 as part of a U.N.-brokered deal boycotted by Haftar," Reuters writes.
Where the battle has moved most recently: south of Tripoli, "in the rural area of Wadi Raba," near an international airport, which is about a half-dozen miles from the coastal center of Tripoli.
Dive deeper: AP just posted a Q&A to help us understand what’s going on today in Libya. You can find that, here.
The U.S. take: “We have made clear that we oppose the military offensive by Khalifa Haftar's forces and urge the immediate halt to these military operations against the Libyan capital,” said SecState Mike Pompeo in a statement Sunday evening. “This unilateral military campaign against Tripoli is endangering civilians and undermining prospects for a better future for all Libyans. There is no military solution to the Libya conflict. This is why the United States continues to press Libyan leaders, together with our international partners, to return to political negotiations mediated by UN Special Representative of the Secretary-General Ghassan Salame.”
U.S. troops pull out. Or, as AFRICOM put it on Sunday, “A contingent of U.S. forces supporting AFRICOM temporarily relocated from Libya in response to security conditions.”
For your eyes only: Here are some of those purported evacuations.  
Said AFRICOM's Gen. Thomas Waldhauser to the WSJ: “The security realities on the ground in Libya are growing increasingly complex and unpredictable.”  

The Sudanese military is under pressure from citizens to abandon their post and stop supporting leader Omar al-Bashir, AFP reports from Khartoum. For the third day, thousands of protesters have swarmed “the army complex -- which also houses Bashir's residence and the defence ministry -- in the biggest anti-government demonstrations for months.”
Why the demonstrations? “The protesters accuse Bashir's administration of economic mismanagement that has led to soaring food prices and regular shortages of fuel and foreign currency… Sudan's protests first erupted in response to a government decision to triple the price of bread. But they quickly morphed into nationwide demonstrations against Bashir's three-decade rule. Officials say 32 people have died in protest-related violence so far, while Human Rights Watch has put the death toll at 51.” Read on, here.

Happening Tuesday evening: An event in DC all about the “Future of Syria,” and how concerned folks can try to help “prevent the Syrian conflict from becoming a forgotten war.”
Hosting the event: The Delegation of the European Union. Things begin at 6 p.m. EST, and the line-up includes a panel discussion — moderated by Defense One’s Kevin Baron — as well as a photographic exhibition titled, "Faces of Resilience: From Syria & The Region." Read more or register for your spot, here.

The U.S. has “revoked the visa of the International Criminal Court's chief prosecutor, [Prosecutor Fatou Bensouda] weeks after warning it would take such an action against anyone from the ICC who is investigating allegations that U.S. personnel might have committed war crimes in Afghanistan,” NPR reported when the news broke on Friday afternoon. Bensouda can still fly to the U.S.; but she is only allowed to visit the UN, according to U.S. officials.
For the record, “While the U.S. claims its citizens and military personnel are outside of the ICC's jurisdiction, the court says Afghanistan is within its purview because the country ratified the Rome Statute, which established the court, in early 2003.” Read on, here.

The Russian navy tested a “Mosquito” anti-ship missile in the Black Sea, the Defence Ministry announced Thursday — with a video to drive the point home.
About the missile: It’s reportedly a “supersonic cruise missile designed to hit surface ships with a displacement of up to 20,000 tons. With a low-altitude trajectory, the rocket has a firing range of 10 to 120 kilometers, but with a high-altitude profile it is able to strike at a distance of 250 kilometers.”
If the missile’s name sounds a little curious, consider Ukraine’s small navy (by comparison) is often referred to as a “mosquito navy.” See, e.g., this piece from Defense One’s Patrick Tucker back in September.
FWIW: NATO began “major” exercises in the Black Sea on the same day Russia’s MoD announced its tests. The NATO drills run through Saturday.
Involved: “14 Romanian warships and six warships from Bulgaria, Canada, Greece, Netherlands, and Turkey, with the participation of approximately 2,200 troops.” Read more, here.
BTW: Last week during its 70th anniversary, NATO members agreed to a “package of measures” to enhance security in the Black Sea region. Georgia and Ukraine are the prime beneficiaries, Secretary-General Jens Stoltenberg said Thursday. The package of measures focuses on “areas such as the training of maritime forces and coast guards. Port visits and exercises. And sharing information.”

The more you know: espionage and architecture edition. A former French spy has passed away in Australia at the age of 97. His name is Joe Bertony, and he was “one of the original engineers of Australia's most recognisable building,” the Sydney Opera House, France24 reports this morning.
“Born on the Mediterranean island of Corsica, Bertony joined the French navy to study naval engineering and was recruited as a spy...He was twice captured by the Germans during World War II and sent to concentration camps, but escaped both times and was later awarded the Croix de Guerre by the French government for his wartime actions.” Bertony passed away at his home in Sydney on Sunday. A bit more, here.

And finally this morning: A man in his 60s was accidentally ejected during a civilian fly-along with a twin-seat Rafale B fighter jet on March 20, Aerotime News reported at the time — but Foxtrot Alpha helped bring the story to our attention. The incident happened in the north of France at the Saint-Dizier air base. “The pilot, whose hands were suffered minor cuts from the broken canopy, managed to land the aircraft safely. The civilian on the other hand apparently parachuted to the runway below, injuring his back in the process.”
In case you were wondering: "His health condition is not a cause for concern," said Col. Cyrille Duvivier, spokesman for the French Air Force. So that’s settled, oui? Read on, here.