Politicians will continue running large deficits as long as the bond market tolerates it by keeping interest rates low. The ultimate correcting mechanism for government spending isn't political discipline, but the bond market's impersonal decision to raise rates, forcing fiscal responsibility.

Contrary to fears of a spike, a major rise in 10-year Treasury yields is unlikely. The current wide gap between long-term yields and the Fed's lower policy rate—a multi-year anomaly—makes these bonds increasingly attractive to buyers. This dynamic creates a natural ceiling on how high long-term rates can go.

While current bond yields resemble pre-2008 historical norms, the fiscal landscape is radically different. Governments now carry much larger debt burdens from the pandemic and other spending. This makes the cost of servicing this debt at historically 'normal' rates a significant and unresolved challenge for the global economy, distinguishing this era from previous ones.

The common narrative blames rising yields on government debt. However, a more significant driver is often strong nominal GDP growth. This environment is actually positive for equities, as it boosts revenues and earnings, making stocks an effective inflation hedge.

Economic models suggest a quantifiable link between government debt and interest rates. A one percentage point increase in the U.S. debt-to-GDP ratio is estimated to push the real neutral interest rate (R-star) up by a significant 3.5 basis points, signaling future pressure on yields.

Historically, surges in U.S. public debt have consistently led to periods of negative real interest rates. This suggests that the sheer weight of government debt creates a structural constraint, forcing markets to keep real rates capped, irrespective of short-term inflation or central bank policy.

While factors like Fed policy play a role, the fundamental cause of rising long-term interest rates is the massive and growing U.S. debt. It's a basic supply-and-demand issue: as more debt is issued, the price of borrowing (interest rates) must increase to attract enough buyers to absorb it.

A new market dynamic has emerged where Fed rate cuts cause long-term bond yields to rise, breaking historical patterns. This anomaly is driven by investor concerns over fiscal imbalances and high national debt, meaning monetary easing no longer has its traditional effect on the back end of the yield curve.

Contrary to the popular narrative focusing on debt, the main force pushing interest rates up is robust nominal GDP growth, fueled by aggressive post-pandemic fiscal policy. This era of 'fiscal dominance' changes the fundamental drivers of the bond market.