The scandal began with a tweet.

“The world wants to invest in Argentina,” Javier Milei, Argentina’s president, posted at 7:01 p.m. on Valentine’s Day, offering a code to buy a new cryptocurrency.

The digital coin was called $Libra, and it had been created 23 minutes earlier.

Over the next few hours, thousands of people invested. $Libra’s value skyrocketed.

Then it swiftly collapsed. The largest stakeholders had sold their coins, leaving almost everyone else with a collective $250 million in losses.

To cryptocurrency veterans, it was a classic “rug-pull.” A celebrity touts a new digital coin, prices soar and then insiders who own most of the coins pull the rug: They sell their stakes for a big profit at the expense of amateur investors who got in later.

To Argentina, it was a national scandal. The president, critics said, had just scammed his constituents. The opposition called for impeachment. Argentine citizens filed a dozen criminal complaints. A federal prosecutor opened an investigation, with Mr. Milei as a target.

Then Mr. Milei left for Washington. At the Conservative Political Action Conference on Saturday, he gave a combative speech ahead of President Trump, the other president who promoted a new cryptocurrency this year that soared and then crashed. That coin, $Trump, generated enormous profits for insiders and a cumulative $2 billion in losses for more than 800,000 other investors.