Today's D Brief: Israel floods Gaza tunnels; More Houthi naval attacks; Russia jamming US arms; WH presses Congress on Ukraine aid; And a bit more.

Nearly two months after Hamas attacked Israel, the Israelis have begun pumping seawater into at least a part of the group’s elaborate tunnel network under the Gaza Strip, U.S. officials told the Wall Street Journal on Tuesday. Flooding the tunnels could take weeks, officials estimate. 

Hamas may be keeping hostages in the tunnels. U.S. President Joe Biden expressed his hesitation over the plan when asked about it Tuesday afternoon at the White House. “Assertions [are] being made that [Israeli officials are] quite sure there are no hostages in any of these tunnels,” Biden said. “But I don't know that for a fact,” he added. 

A second opinion: “The tunnels are military objectives liable to attack,” writes Aurel Sari, who teaches Public International Law at the University of Exeter. Sari wrote at length considering the legal implications of flooding those tunnels, and decided, “Filling them with water would not be an indiscriminate attack,” but “the reverberating effects may be far more significant, in particular if they were to drastically reduce the availability of potable water to the civilian population and lead to high levels of injury and death.” Read more, here

Changing winds? On Monday, Biden warned at a fundraiser that Israel still “has most of the world supporting it.” However, he cautioned, “they’re starting to lose that support by the indiscriminate bombing that takes place.” 

Birds-eye view of Gaza: The New York Times produced an impressive and sobering multimedia explainer demonstrating the scale of devastation Israel has wrought on the Gaza Strip. 

Newly revealed: The U.S. quickly upgraded Israel’s F-35s after Hamas’ Oct. 7 attack, Pentagon acquisition chief Bill LaPlante told lawmakers on Tuesday. The Pentagon gave Israel special computer files with detailed information about enemy threats. Defense One’s Audrey Decker has more, here.

Developing: White House National Security Advisor Jake Sullivan is headed to Israel on Thursday and Friday for talks with Prime Minister Benjamin Netanyahu and “his war cabinet,” the administration said Wednesday. 

SecDef inbound, too. Pentagon chief Lloyd Austin is traveling to the Middle East this week “to step up the international efforts to protect the free flow of commerce through the Red Sea,” Biden said Tuesday. 

Houthis naval attacks continue: The U.S. Navy shot down another drone launched from Houthi-controlled Yemen, the Associated Press reported Wednesday. Crew on the USS Mason downed the drone as it approached their ship, according to U.S. officials. 

The Houthis also launched two missiles at a commercial tanker loaded with jet fuel as it transited the Bab el-Mandeb Strait separating Yemen from Africa on Wednesday. Fortunately the missiles missed the tanker Ardmore Encounter as it traveled north toward the Suez Canal. Armed guards aboard the Encounter also reportedly “opened fire to drive off skiffs loaded with men trying to board the vessel,” AP writes. 

“No one boarded the vessel and all crew members are safe and accounted for,” the owners of the ship said in a statement. “The vessel remains fully operational with no loss of cargo or damage on board,” they added. 

A separate ship was followed by at least 5 small gunboats for nearly 90 minutes off the coast of Oman on Wednesday, according to British maritime authorities (PDF). The boats each had three people on board who “appeared to be in grey uniforms.” The boats eventually “cleared the area” and crew onboard the larger vessel are safe.  

Worth noting: The French have for at least two episodes now helped the U.S. Navy respond to the Houthis antagonism in the Red Sea. That includes shooting down one drone near Yemen on Monday, and two others on Saturday. 

Reminder: It’s the Saudis who want the U.S. to refrain from attacking the Houthis in Yemen, according to Reuters, reporting last week. Read more, here

Related reading: Flooding Hamas tunnels could harm Gaza’s freshwater for generations, warns academic,” the Times of Israel reported last week.

Welcome to this Wednesday 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. Happy 387th birthday to the National Guard! The militia organization reckons its age from the 1636 establishment of three regiments whose lineal descendants are today the oldest in the U.S. military: the 181st Infantry, the 182nd Infantry, the 101st Field Artillery, and the 101st Engineer Battalion of the Massachusetts Army National Guard.

While the future of U.S. aid to Ukraine hangs in the balance on Capitol Hill, the Pentagon announced another $200 million in weapons for Kyiv on Tuesday. That includes AIM-9M air defense missiles, more High Mobility Artillery Rocket System munitions, 155mm and 105mm artillery rounds, radar-seeking missiles, and more.

“More than 90% of our security assistance to Ukraine has been spent in the United States to provide weapons for Ukraine and replenish our stockpiles and build our industrial base,” President Biden said Tuesday while standing beside Ukrainian President Volodymir Zelenskyy. 

Forecast from Capitol Hill: Senate Minority Leader Mitch McConnell told Senate Republicans during lunch on Tuesday “that the Ukraine/border talks are not going anywhere this year, and that it’ll be punted to January,” Andrew Desiderio reported for Punchbowl

But Biden said a deal with Republicans could be coming soon. “My team is working with Senate Democrats and Republicans to try to find a bipartisan compromise, both in terms of changes in policy, and provide the resources we need to secure the border,” the president said Tuesday. “Compromise is how democracy works,” he said, but cautioned, “Holding Ukraine funding hostage in an attempt to force through an extreme Republican partisan agenda on the border is not how it works.”

There are a “small number of Republicans who don't want to support Ukraine, but they don't speak for the majority,” Biden said. And while he said he won’t make any promises, he told reporters he is “hopeful we can get there. I think we can.”

Meanwhile, a U.S. general says Russia has found a way to jam various U.S. precision munitions brought to Ukraine, Defense One’s Sam Skove reported Tuesday. CNN had previously reported some jamming this past May. And leaked U.S. documents also stated that Russia was jamming GPS-guided bombs that the U.S. had given to Ukraine.

Update: Staggering losses for Moscow. Ukraine has allegedly killed or injured 315,000 Russian military personnel since Vladimir Putin’s full-scale invasion began, which is equivalent to about 87% of Russia’s prewar army of about 360,000 soldiers, according to a declassified assessment released Tuesday by the White House’s National Security Council to outlets like the New York Times

Russia has also lost 2,200 of its 3,500 tanks to Ukraine, which has forced the Kremlin to “pull 50 year old T-62 tanks from storage,” the Times reported Tuesday. 

And just since October, when Russia launched its own offensive to continue invading unoccupied parts of Ukraine, “the Russian military has suffered more than 13,000 casualties along the Avdiivka-Novopavlivka axis and over 220 combat vehicle losses-the equivalent of 6 maneuver battalions in equipment alone,” National Security Council spokeswoman Adrienne Watson said in a statement. 

Why bring this up now? “It is more critical now than ever that we maintain our support for Ukraine so they can continue to hold the line and regain their territory,” Watson said. “Russia seems to believe that a military deadlock through the winter will drain Western support for Ukraine and ultimately give Russia the advantage despite Russian losses and persistent shortages of trained personnel, munitions, and equipment.”

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