For the next three days, one man holds the global economy in the palm of his hands, literally and figuratively. And almost no one but him knows what will happen, Axios' Courtenay Brown and Ben Berkowitz write.

• Why it matters: Every Wall Street trader and economist has "April 2" circled on their calendars. The consensus is that tariffs are coming, but the fear is in the unknown: how aggressive the measures will be.

Financial markets hate surprises. Yet that is what the Trump administration looks set to do this week with mixed signals from the president himself about what will happen on Wednesday.

• The uncertainty, already tanking the stock market and economic sentiment, might be swapped for an unprecedented trade regime that would force businesses to adjust virtually overnight.
• "[W]e are sort of off the charts in our 'unknowns' inventory," Mark Malek, chief investment officer at Siebert Financial, wrote in a Friday note.

🔎 Zoom in: Trump has warned about reciprocal tariffs for more than six weeks — a wide-ranging plan meant to hit back at nations said to have unfair trade practices.

• He has called it "Liberation Day," saying the tariffs would free American exporters that have been ripped off by other countries' trade restrictions, which the administration defines loosely.

💰 Peter Navarro, the White House senior counselor for trade and manufacturing, told Shannon Bream on "Fox News Sunday" yesterday that Trump's tariffs on auto imports, which take effect Wednesday, will raise about $100 billion per year, and additional tariffs will raise about $600 billion per year — "about 6 trillion over a 10-year period." (Watch the video.)

🧮 By the numbers: The S&P 500 is down almost 9% since Feb. 13, when Trump unveiled a memo directing the Commerce Department to look into reciprocal tariffs.

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The U.S. is freezing research funding, canceling projects, firing thousands of federal scientists and creating an atmosphere of uncertainty that scientists warn could slam the brakes on progress, Axios' Erica Pandey and Alison Snyder write.

• Why it matters: America has enjoyed decades of dominance in science and technology — plus the economic boom, medical advancements and global influence that come with it.

Now, as the U.S.'s global lead is contested and competition for the world's top talent gets stiffer, the Trump administration is disrupting the system that has propelled the country.

• "There are some immediate effects. People will be laid off, talent will go elsewhere, some research groups will shut down," says Chris Impey, an astronomer at the University of Arizona.

🧠 Stunning stat: 40% of U.S.-affiliated Nobel Prize winners in the sciences — physics, chemistry and medicine — between 2000 and 2023 were immigrants.

• Funding resources, top-notch universities, research freedom and a diverse culture that supports innovation are among the factors that have made the U.S. a global magnet for scientists.

🧪 The stakes: The U.S. could see a two-fold brain drain: fewer foreign scientists coming to America, and American talent heading to other countries.

• The upheaval has also been an opportunity for China and Russia: Both are trying to recruit former federal scientists.
• Universities and research centers in Europe are earmarking money to hire U.S. scientists.

🥊 What they're saying: White House and DOGE officials argue changes to the system will boost research, not stifle it. For example, they say funding switch-ups, like cutting the dollars NIH provides institutions for overhead costs, will free up more funds for science.

• But universities say these administrative costs are a critical piece of conducting research.

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Elon Musk's announcement on Friday that his AI company xAI will acquire X is the strongest sign yet that the AI business is devouring the social media world, Axios' Scott Rosenberg writes.

• Why it matters: Musk's move is a maneuver to spruce up his overall financial picture — leveraging the AI industry's fizzy valuation arithmetic to shore up X's stagnant revenue and debt-loaded capital structure.

🔬 Between the lines: The entire social media world — including X, Meta-owned Facebook and Instagram, Google-owned YouTube, even the younger TikTok — has become a legacy platform.

• While this inherited business is still huge and in many cases profitable, it's not going to grow or innovate at the pace Silicon Valley and Wall Street demand.

The bottom line: xAI gives Musk a convenient vehicle to scoot X out of the tarnished social media category and into the AI world.

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Elon Musk rocks a cheesehead during a Green Bay rally before tomorrow's Wisconsin state Supreme Court election.

• He gave out $1 million checks to two voters, and said the election was critical to Trump's agenda and "the future of civilization."

"The reason for the checks is ... really just to get attention," Musk told the crowd. "It causes the legacy media to, like, kinda lose their minds. And then they'll run it on every news channel. ... It would cost, like, 10 times more ... to get the kind of coverage that it gets." (30-sec. video)

Musk and groups he supports have spent more than $20 million to help conservative favorite Brad Schimel.

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President Trump told NBC News "there are methods" by which he could serve a third term in the White House — a highly improbable idea some MAGA allies have endorsed.

• "No I'm not joking. I'm not joking," Trump told "Meet the Press" moderator Kristen Welker in a phone interview from Florida.

Reality check: There's no chance the required two-thirds of Congress and three-quarters of the states would vote to abolish the 22nd Amendment.

✈️ Talking to reporters aboard Air Force One last night, Trump said:

"I don't even want to talk about a third term now, because no matter how you look at it, you've got a long time to go. ... We have almost four years to go and that's a long time. But despite that, so many people are saying: You've got to run again."

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In his widely read letter to investors out this morning, BlackRock CEO Larry Fink reassures investors that this moment of economic anxiety will pass, Axios' Emily Peck writes.

• Why it matters: Fink runs the world's biggest asset manager and is hugely influential. His annual letter reflects top business trends.

Fink treads cautiously in the 27-page letter, never explicitly mentioning President Trump, and only touches on politics glancingly at the top:

"I hear it from nearly every client, nearly every leader — nearly every person — I talk to: They're more anxious about the economy than at any time in recent memory. I understand why. But we have lived through moments like this before. And somehow, in the long run, we figure things out."

Read the letter ... Go deeper: 5 highlights from the letter ... Ben Geman contributed reporting.

President Trump plans to travel to Saudi Arabia in mid-May on his first foreign trip since returning to the White House, Axios' Barak Ravid and Alex Isenstadt scoop.

• Why it matters: Trump's decision to go to Saudi Arabia on his first foreign trip signals how close the relationship between the Trump administration and Gulf countries has become, especially when it comes to economic cooperation and investment.

👓 Between the lines: Trump's first foreign trip during his previous term was also to Saudi Arabia, at roughly the same time.

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Leland Vittert — anchor of NewsNation's prime-time "On Balance" — will be out Sept. 30 with "Born Lucky: A Dedicated Father, A Grateful Son, and My Journey with Autism," chronicling his dad's role in coaching him from childhood struggles to the journalistic heights of war and political coverage.

• "This book is about giving hope to tens of millions of parents whose kids are struggling every day — not just with autism and the spectrum, but ADHD, learning disabilities, anxiety, bullying and the difficulties of growing up," says Vittert, 42, whose childhood nickname was "Lucky."

The backstory: Vittert, also author of the newsletter "War Notes," showed early signs "of being autistic — a term rarely used at the time — struggling with social cues, communication, and behavioral norms," says the announcement from the publisher, Harper Horizon.

• Vittert's father, Mark, sold his company and "became a full-time parent-coach, training Leland and teaching him the skills he needed to navigate in society."

In a YouTube book trailer, Vittert says from his anchor desk, the Capitol dome over his shoulder: "I'm living proof you don't have to be defined by your diagnosis. As a little boy, child psychologists told my parents I had what we now know as autism. ... I didn't talk until I was 3."

• Vittert says that at a time when he had no friends and was called "weird," his dad "knew the world wouldn't change for me. He had to change me for the world." When "Lucky" was 7, his dad had him doing 200 pushups a day to give the bullies a run for their money.

Watch the trailer ... More on the book.

For the first time since 2008 — and only the second time ever — all No. 1 seeds have reached the men's Final Four.

• Auburn will face Florida ... Duke takes on Houston.

🎲 The favorite: Duke — with superstar Cooper Flagg — is the frontrunner to win the title, followed by Florida, Houston and Auburn, according to BetMGM Sportsbook.

📺 How to watch: Semifinals start on Saturday (6:09 p.m. ET, CBS) from the Alamodome in San Antonio.