Today's D Brief: State of Defense 2024; Anti-ISIS actions; Iranian lull; Red Sea skirmishes; And just a bit more.

State of Defense 2024: Once a year, Defense One takes a look at how the services are modernizing and positioning for the year ahead. Read:

• State of the Army: The cancellation of a scout helicopter just might signal a new era of agility. (Sam Skove)
• State of the Navy: Amid program delays and budget choices, the new CNO vows more learning and “more players on the field.” (Bradley Peniston)
• State of the Air Force: A strategic reorientation is unfolding against changes in the conduct of air warfare. (Audrey Decker)
• State of the Marine Corps: The Corps' race to become a lighter service might move faster if its budget weren’t flat. (Sam Skove)
• State of the Space Force: The young service is focusing on contested space—even as its budgets return to Earth. (Audrey Decker)

And watch our interviews with the services' top leaders:

• Gen. Randy George, Army Chief of Staff
• Adm. Lisa Franchetti, Chief of Naval Operations
• Gen. David Allvin, Chief of Staff of the Air Force
• Gen. Christopher Mahoney, Assistant Commandant of the Marine Corps
• Gen. Chance Saltzman, Chief of Space Operations

The entire package of video interviews with service leaders, outside experts, and more is available at the State of Defense 2024 event page.

Welcome to this Tuesday edition of The D Brief, brought to you by Ben Watson with Bradley Peniston. Share your newsletter tips, reading recommendations, or feedback for the year ahead here. And if you’re not already subscribed, you can do that here. On this day in 1940, Nazi Germany invaded Denmark and Norway.

Pentagon leaders are testifying on their latest budget request Tuesday morning before the Senate Armed Services Committee. Defense Secretary Lloyd Austin is joined by Joint Chiefs Chairman Air Force Gen. Charles Q. Brown, as well as Comptroller Mike McCord. That began at 9:30 a.m. ET. Catch what remains of that livestream via SASC, here.   

And Air and Space Force leaders are testifying on their fiscal 2025 budget request before Senate appropriators. Air Force Secretary Frank Kendall is joined by his chief Gen. David Allvin and Chief of Space Operations Gen. B. Chance Saltzman. That got under way at 10 a.m. ET. Livestream it here.

In its war against ISIS, U.S. forces in the Middle East averaged more than a mission per day from January to the end of March, defense officials from Central Command announced late last week in a quarterly update. Most of the operations (66 of 94) occurred in Iraq and led to 11 alleged terrorists killed and three dozen detained. The remaining 28 operations took place in Syria and led to seven killed and 27 militants detained. 

U.S. intelligence officials estimate that some 2,500 ISIS fighters remain across Iraq and Syria. There are another 9,000 fighters detained in Syria; and more than 45,000 individuals and families of militants are still quarantined at the Al Hol and Al Roj camps, CENTCOM said. 

Worth noting: ISIS has notably escalated its attacks against Syrian troops this calendar year, with such violence rising by 170% in Assad-held areas and “consecutive month-on-month 30-40% increases” in the country’s northeast where U.S.-backed Syrian forces operate, Charles Lister of the Middle East Institute flagged on social media last week.

Opinion: Historian Max Boot argues President Biden somewhat quietly notched an “unheralded victory” over the past two months following U.S. strikes against Iran-backed militia leaders inside Iraq and across the border in Syria. Writing in the Washington Post Monday, Boot emphasizes the aggressive road encouraged by hawkish Republicans like Lindsey Graham and Tom Cotton, both of whom advocated direct strikes inside Iran following the late January drone attack on a U.S. base in Jordan that killed three American soldiers and wounded more than 40 others. 

“Luckily, Biden, with his decades of foreign policy experience, chose a more prudent path” with the U.S. strikes against those militia leaders in the first week of February, Boot writes. “The clear message was that other Iranian commanders would be next if they didn’t knock off their attacks against U.S. troops. And guess what? Iran did stop.” 

Granted, those Iran-backed militants have turned their sights more squarely to Israel in recent weeks, including a “big overnight attack wave…using 351/Paveh type cruise missiles,” Mike Knights of the Middle East Institute noted Tuesday on social media.  

Indeed, “April is now (just 9 days in) the most active month on record for anti-Israel claimed strikes at the Islamic Resistance in Iraq,” Knights reports. And with Iraq’s prime minister scheduled to visit the White House next week, “he'll be arriving with his country being used as a launch pad for Iran-provided cruise missiles,” Knights says. 

Boot acknowledges the lull is probably just a temporary victory for Biden, but the outcome (at least presently) has yielded a dramatic decline in attacks on U.S. troops in Iraq and Syria. “We’re not under any illusions,” a defense official told Boot. “Under certain circumstances, attacks could restart, but we demonstrated that we’re willing and able to defend our forces.”

But Biden should pivot to Yemen and order “a more sustained air campaign” to dissuade that Iran-backed group from its persistent attacks on commercial shipping and military vessels in the Red Sea and the Gulf of Aden, Boot says. Finding a useful middle ground by responding to Iran-linked actors in the region without provoking wider conflict is an incredible challenge, he concedes. After all, “This is one of those international problems so difficult that it cannot be solved, at least not in the foreseeable future. It can only be managed,” says Boot. Read the rest, here. 

Related reading: 

• “6 months into Israel-Hamas war, Palestinians return to southern Gaza city Khan Younis to find ‘everything is destroyed’,” CBS News reported Tuesday; 
• “Iran Smuggles Arms to West Bank, Officials Say, to Foment Unrest With Israel,” the New York Times reported Tuesday;
• “Turkey imposes export restrictions on Israel until Gaza ceasefire,” Reuters reported Tuesday from Ankara;
• “Turkey restricts exports to Israel, saying its request to airdrop aid to Gaza was denied,” CNN reported Tuesday; 
• “Google Workers Revolt Over $1.2 Billion Contract With Israel,” Time reported Monday; 
• And “As Palestine applies for full UN membership, what’s in the way?” al-Jazeera reported Tuesday in an explainer. 

Near Yemen, U.S. forces destroyed a Houthi “air defense system with two missiles ready to launch” as well as a ground control station in Houthi-controlled areas of the war torn country, CENTCOM said Monday. A drone apparently launched by the Houthis over the Red Sea was also destroyed before reaching any targets on Monday, according to CENTCOM.

And early Sunday, the Houthis fired another anti-ship ballistic missile toward a commercial ship transiting the Gulf of Aden. The target seemed to be the M/V Hope Island, a Marshall Islands flagged, U.K. owned, Italian operated cargo ship. Fortunately no one was injured and the ships were unharmed. However, “This was the fifth observed missile launch against this coalition ship and M/V Hope Island,” CENTCOM said. 

Another coalition ship intercepted an anti-ship missile Saturday evening, several hours after U.S. forces destroyed a mobile surface-to air missile system and separately shot down an aerial drone over the Red Sea, defense officials said Sunday.