The Fed left interest rates alone, and the real reason may be a weakening job market — a warning sign for workers.

• The Fed is holding rates steady, but the quiet reason is that jobs may be getting weaker, not that everything is fine.
• Early data on weekly job gains is starting to turn down, hinting at more job losses ahead.
• The Fed doesn't want to keep rates high and make those job losses worse if it can avoid it.
• Publicly they blame the market for higher rates, while privately they're watching the labor market closely.

Outlook: If hiring keeps slipping, expect the Fed to shift toward cutting rates to head off an employment crisis.