Federal Reserve President Jerome Powell has unleashed his inner hawk.
He will tighten monetary policy until inflation goes down significantly, he announced.
The latest inflation figures from August had caused a slight shock because their release had shattered all hopes that the worst might be over.
Powell had already made it clear in the spa town of Jackson Hole that from now on the Fed's exclusive fight would be inflation and that he considered painful therapy to be necessary.
What exactly contributed to this reversal is difficult to say.
However, concerns that the inflation expectations of entrepreneurs, businesspeople and ordinary citizens could start to slide certainly played a role.
Once people start pricing higher inflation into their business decisions, there's little stopping them.
Recently, Powell has frequently recalled the legendary Fed chairman Paul Volcker, who curbed inflation in the early 1980s with high key interest rates and accepted two short, painful recessions to do so.
Previously, its predecessor had tried to get inflation under control with less decisive measures.
Powell now seems to have internalized this lesson, too.
After Wednesday's rate decision, he prepared the markets for two more rate hikes this year.
The determination will only wane in the coming year, when the central bankers only expect one rate hike.
If you're not too optimistic.