The Treasury is buying back long-term bonds to push down borrowing costs before the midterms, and the odds are it won't work.

• Long-term interest rates have jumped since March, dragging mortgage rates up with them.
• The Treasury is selling short-term debt to buy long-term debt, hoping to force long rates back down.
• That's yield curve control by another name, not money printing — the Fed's balance sheet isn't growing.
• Every past round of bond buying ended with rates higher than when it started, because long rates follow growth and inflation, not government debt or official meddling.
• When rates spike, banks and funds pile into government bonds for the easy yield, which pulls rates back down on its own.

Outlook: Interest rates are likely lower a year from now, as long as oil stays near current levels and the Middle East doesn't blow up again.