Over the course of the Iran war, the Trump administration has learned it can trigger big declines in the price of oil with well-timed messages predicting imminent peace deals. Now, Treasury Secretary Scott Bessent is trying the same trick with the bond market.

Apparently alarmed by the upward march in long-term yields, the U.S. Treasury said this morning it would at least double repurchases of longer-dated Treasury bonds. Rates dived in reaction, with the yield on 30-year Treasury bonds falling 0.09 percentage point to 5.20%.

But the size of the planned repurchases is miniscule, doubling from $2 billion to $4 billion per operation. In July alone, the Federal budget deficit was $432 billion. The existence of this deficit means the Treasury's firepower to buy back debt is inherently limited. In effect, it can only buy back long-term bonds by issuing more short-term ones.

To have a sustained impact on long-term yields, there would have to be meaningful deficit reduction, which is unlikely, to say the least, in the current political environment. Alternatively, the unlimited firepower of the Federal Reserve could be brought to bear on the Treasury market in an explicit policy of "yield curve control."

Similar to what the Bank of Japan did for years, this would involve the Fed stepping in to buy bonds when yields go above a certain threshold. But this would fly in the face of Kevin Warsh's rhetoric on multiple fronts, including wanting a smaller Fed balance sheet and allowing the market to send clearer signals absent influence from the central bank.

Unless there is a huge reversal from Warsh, the Trump administration's attempts to jawbone the Treasury market will look similar to its efforts on oil: Effective at triggering short-term market moves, but not at arresting the long-term trend. For that, the fundamental causes of the problem need to be addressed. That's not something Bessent can talk away.