Can the US Military Rescue US Treasuries?

We have an ultimate means of intervention

On August 21, Trump answered reporters' questions before Air Force One. Asked what other tools were available to intervene as Treasury yields rebounded, he gave an impromptu reply: there were many ways to intervene, and the military was the ultimate means, which would be used if necessary. This was an oral response at the scene, not an official US policy document. It raises a macroeconomic question worth examining: can geopolitical conflict really support Treasuries?

Yields that face upward pressure will not necessarily fall

A simple view circulates in markets: when conflict breaks out, global safe-haven money flows into Treasuries and lowers yields. But a review of seven historical episodes shows that conflict can produce only a brief safe-haven impulse. Over the medium and long term, fiscal pressures and inflation often overwhelm it.

World War II is the only case that appears to have succeeded, but it was not a spontaneous market outcome. The Fed imposed wartime yield-curve controls, fixing a 2.5% ceiling on the 10-year Treasury yield. Publicly held debt fell from 109% of GDP in 1946 to 67% in 1951. Wartime price controls and postwar nominal economic growth diluted the debt burden; military action itself did not cause that result.

During the Vietnam War, the initial safe-haven effect was limited. Military and social-welfare spending expanded together, pushing up inflation. The 10-year Treasury yield rose from 4.2% to 6.5%, helping set the stage for the high inflation of the 1970s and 1980s.

The decline in yields during the Gulf War owed more to the US recession and Fed rate cuts than to any benefit from the conflict. After September 11, safe-haven buying briefly lowered yields, but the subsequent large expenditures on counterterrorism continued to increase the fiscal burden.

In 2026, the same mechanism lasted only 48 hours. Why? At the start of the war, safe-haven demand briefly pushed the 10-year yield down to 3.93%. Oil-price increases and fiscal concerns then drove it above 4.72%, while the 30-year yield rose to 5.31%, its highest level since 2007. The impulse was short and the reversal much faster than in previous episodes. The key change is that confidence in US fiscal creditworthiness has now weakened markedly.

What are safe-haven investors seeking?

They are seeking sovereign creditworthiness, not military force itself. Conflict brings short-lived safe-haven buying, but it also raises oil prices and inflation expectations. Higher military expenditure expands fiscal deficits and bond supply, ultimately pushing yields higher.

What should we keep tracking?

1. Treasury buybacks on September 9.

2. The Treasury's November 4 refunding meeting.

3. Changes in long-term Treasury yields.

The short-term safe-haven impulse is real, but it cannot solve the debt problem at its root. What can stabilise Treasuries is a manageable fiscal deficit and market confidence, rather than a temporary inflow of money caused by conflict.