Swarms of low-cost drones powered by AI — perhaps hundreds of them at the same time — could soon pose an existential threat to America's hulking war machinery.

• Why it matters: Advanced militaries can largely fend off individual drones. But swarms of them deployed on a single target have the potential to reshape the global balance of power.

The big picture: Future battles will be fought with a connected mix of cheap weapons — not sophisticated weapons systems that only superpowers can afford, retired Adm. James Stavridis and Marine veteran Elliot Ackerman argue in a Wall Street Journal essay.

• Expensive aircraft carriers or stealth bombers, which require massive time commitments to develop and build, will become vulnerable to drones that almost every military and armed group can access.

🔎 Zoom in: The use of lethal drones has exploded in conflicts around the world.

• They've changed the trajectory of the war in Ukraine multiple times. Houthi militants are aiming them at ships.
• Those are largely point-and-shoot weapons controlled remotely by individual combatants, and American soldiers and ships are typically capable of shooting them down.
• But if they're deployed in a swarm, Iranian-supplied drones that cost thousands of dollars each could take on multibillion-dollar warships.

🪖 State of play: The Pentagon is racing to develop a defense against swarms while building AI-coordinated drone systems of its own.

• The Defense Department has signed at least five deals with contractors that explicitly reference swarming, according to a report from the Center for Security and Emerging Technology that examined procurement contracts from 2020.

Army Gen. Erik Kurilla, commander of U.S. Central Command, told the Senate Armed Services Committee last week that cheap drones are "one of the top threats."

• He said the U.S. should "continue to invest in things like high-powered microwave" weapons to defend against mass drone attacks.

The bottom line: "Warfare is headed toward a brain-on-brain conflict," Stavridis and Ackerman write.

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The White House sent a letter to House Speaker Mike Johnson (R-La.) early this morning with a clear message: Your impeachment inquiry of President Biden is over, Axios' Stephen Neukam writes.

• Why it matters: The letter signals the White House's increasingly aggressive offense on impeachment, as Democrats see the GOP inquiry fizzling out.

The letter to Johnson from White House Counsel Edward Siskel comes as a growing number of Republicans acknowledge that impeaching Biden is unlikely. Johnson hasn't committed to holding a vote on any impeachment articles.

• "It is obviously time to move on, Mr. Speaker. This impeachment is over," Siskel wrote, calling the effort a "charade."

Keep reading.

The day after the Oct. 7 terrorist attack on Israel by Hamas, President Biden was already talking about it as a world-altering event that could reverberate through the 21st century, Axios' Barak Ravid and Alex Thompson write.

• Why it matters: The president's raw reaction to the attack is captured in the transcript from his five hours of interviews with special counsel Robert Hur on Oct. 8 and 9.

At several moments during the interviews, Biden references the events in Israel.

• "I think the world goes through these major inflection points where what's happening at that moment — and the two, four years around either side of it — and the outcome of those discussions determine what the next six, seven decades look like," Biden said.
• "I think that's where we are right now. For example, I think the Israeli thing has changed it all."

Keep reading. ... Read the transcript.

Spring is getting warmer on average nationwide — a trend that reflects human-caused warming, Axios' Alex Fitzpatrick and Alice Feng write from a Climate Central analysis.

• Why it matters: Much of the climate change discussion is focused on summer and winter. But the "between seasons" are affected too.

Average spring temperatures warmed by 2.2°F from 1970 to 2023 across nearly 230 U.S. cities.

• The highest average springtime temperature increases were seen in Reno (+6.8°F), El Paso (+6.3°F), and Las Vegas (+6.2°F).
• A hotter spring could mean longer allergy seasons, changes for farming and an earlier snowmelt (which in turn affects drinking water supplies).

Stunning stat: Spring has gotten notably hotter in the American Southwest, where average seasonal temperatures have risen by more than 6°F in some places.

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"America's extraordinary economy keeps defying the pessimists," The Economist writes in a new cover story.

• Why it matters: "America has thrived as its companies and workers have innovated and adapted to a rapidly changing world," the magazine concludes.

Between the lines: "America has 4% more workers than it did at the end of 2019, thanks in part to rising workforce participation, but mainly owing to higher immigration," The Economist notes. "The foreign-born population is up by 4.4m, a figure which may undercount those who arrived illegally. "

• "Other long-standing strengths have made America enviably placed to cope with geopolitical tumult. Its vast internal market encourages innovation and means it depends less on foreign trade than smaller rich economies do."
• "Because the shale boom of the 2010s made America a net energy exporter, it has in aggregate benefited rather than suffered from the high energy prices that hit the wallets of Europeans."

Reality check: "Official forecasts show that America will this year spend more on debt interest than national defense. More borrowing risks building up financial perils in the future."

Uber and Lyft are threatening to stop serving Minneapolis later this spring over a new law that significantly increases driver pay, Axios Twin Cities' Kyle Stokes writes.

• The ordinance adds a pay floor that would put wages around the equivalent of the local minimum wage ($15.57 an hour).

Why it matters: As many as 8,000 Twin Cities residents drive for Uber and Lyft. And for so many of us, ride-hailing services are part of daily life.

• Lyft said the new law was "deeply flawed, and the rates it sets are far higher than the state's study suggested."

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Neil Irwin and Courtenay Brown, co-authors of the midday Axios Macro newsletter, and business managing editor Javier David won a top award in the 29th annual contest of the Society for Advancing Business Editing and Writing (SABEW).

• Axios was honored in the newsletter division for coverage of how the resilient U.S. economy thwarted a predicted recession.
• "The judges were impressed," the citation says, "by Axios Macro's engaging, snappy style and insightful analysis, which consistently unpacks complex issues for readers and helps them understand how economic trends and other major business news affect their daily lives — and their wallets."

In Media/Entertainment, honorable mention went to Axios media trends expert Sara Fischer and tech managing editor Scott Rosenberg for persistent, illuminating coverage of Forbes' efforts to sell itself.

• "This was an impressive collection of stories showing excellent sourcing and investigative skills," the judges wrote. "Using Axios' distinctive 'bullets' style, the writers laid out why this matters, what readers should look out for and what the stakes are."

Click here for Axios Macro ... Get Axios Media Trends. ... Full list of winners.

Easter is two weeks away. Halloween is more than seven months away. But Home Depot is promoting a 5-foot skeleton dog, a 12-foot skeleton and a 7-foot animated Frankenstein.

• Why it matters: There's an arms race among retailers to move holiday merchandise earlier and earlier, Axios' Kelly Tyko writes.

"This is the earliest we have ever announced any of our Halloween products," The Home Depot told Axios in a statement. "We wanted to share what is coming for our Halloween superfans."

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