We’re about to find out if the crypto market is big enough to raise the price of U.S. bonds and the dollar

• President Trump’s GENIUS Act legalizes stablecoins and requires them to be backed by U.S. dollars or Treasuries. That’s going to increase demand for dollar-backed assets and, maybe, cement the dollar’s reserve currency status. Bitcoin and Ether have both risen as a result, alongside a modest recovery in the U.S. dollar.

Bitcoin is up. Ether is up. And the dollar is up—a little. These things might be related if you believe, as many in the cryptocurrency world do, that the...