The Sustainability of the Interest-Rate Path: Answering John Cochrane from Within His Own Framework

John Cochrane poses a deep and honest question in “Reasons to Lower Rates.” In his best models—featuring long-term debt, a generalized Phillips curve, long-run neutrality, and long-run stability—a persistent reduction in interest rates, once the maturity structure of the debt has been shortened, can lower inflation in both the short and the long run. The channel is dual: the long-run Fisherian mechanism and, crucially, the lower interest burden on the outstanding stock of debt, which eases fiscal pressure. Cochrane acknowledges the result but wonders whether he truly believes it enough to defend it in public. He asks whether he should show more courage, as Milton Friedman did in his celebrated presidential address to the American Economic Association.¹

In the immediate follow-up, “More on lower rates,” Cochrane deepens the same logic and offers a second route to “immaculate” disinflation: announce the lower interest-rate path far enough in advance. The short-run contrary movement that appears in his simulation with long-term debt arises because long-term bond prices adjust to the announcement—or to the change in expectations. If the announcement is made with sufficient lead time—ideally so that most currently outstanding debt matures before the lower rates take effect—that adverse short-run movement is attenuated or disappears. Given the relatively short average maturity of U.S. debt, three to five years of advance notice might suffice to eliminate most of the contrary effect. Cochrane recognizes, however, that this would require a return to more credible forward guidance and a greater degree of rule-following than the Federal Reserve currently appears willing to practice.¹

The answer to both formulations of the question lies in his own text, in Friedman, and, especially clearly, in the recent Argentine experience. Not as a recommendation of financial repression, but as empirical support for the mechanism Cochrane himself has formalized.

Cochrane’s Theoretical Framework

Cochrane has long insisted that monetary policy does not operate in a fiscal vacuum. In The Fiscal Theory of the Price Level and subsequent work, the price level reflects the relationship between the real value of nominal government debt and the expected, discounted sequence of future primary surpluses. When the central bank sets the interest rate and fiscal policy does not adjust to absorb the higher—or lower—rollover costs, the result is an intertemporal redistribution of inflation: less now, more later—or vice versa.¹

In “Reasons to Lower Rates” he presents three experiments. With long-term debt, cutting rates produces a temporary rise in inflation followed by a permanent decline. With overnight debt, inflation falls immediately and persistently. Hence the logical recommendation: first shorten maturity, then lower rates in a sustained manner. The fiscal relief from lower interest costs reinforces the anchor. In the follow-up he adds the alternative of pre-announcing the path with sufficient lead time so that the long-term-debt mechanism does not generate the opposite short-run movement. In both cases the critical assumption is the same: fiscal policy held constant—or, more broadly, kept consistent with the new interest-rate path.¹

The weak point is the credibility and duration of that lower-rate path. Here Friedman enters.

Friedman and the Problem of Time

In his presidential address, published in 1968, Friedman not only denied the permanent inflation–unemployment trade-off. He also made clear that a central bank cannot arbitrarily peg the nominal interest rate for a prolonged period. An attempt to hold rates down through monetary expansion can ultimately produce the inflation expectations that drive nominal rates upward.² Read through Cochrane’s fiscal framework, the warning is that artificially low rates cannot indefinitely compensate for an inconsistent policy regime.

Friedman’s lesson is temporal: an interest-rate policy must be judged by what happens over time, not merely by its immediate effects. Within Cochrane’s framework, its sustainability depends on consistency with the complete fiscal path, including debt service. Cochrane already incorporates that consistency into his models by treating the fiscal outcome as the ultimate determinant. The residual empirical question is whether a government can sustain a lower-rate path “by fair means”—credible primary surpluses, voluntary maturity shortening, or credible pre-announcement—or only “by foul means”: repression.

The Argentine Case as Validation, Not Prescription

Argentina under Javier Milei offers a striking empirical illustration of Cochrane’s framework. Cochrane himself has publicly emphasized the significance of the episode. He has noted that inflation fell sharply without a prior period of high real interest rates and has attributed the outcome primarily to the fiscal turnaround and the associated change in expectations.³

The magnitude of that turnaround is substantial. According to the IMF, the federal government moved from a primary deficit of 2.8 percent of GDP and an overall deficit of 5.0 percent in 2023 to surpluses of 1.8 percent and 0.3 percent, respectively, in 2024. In a single year, the fiscal improvement amounted to 4.6 percentage points of GDP in the primary balance and 5.3 percentage points in the overall balance.⁴

The facts are consistent with the mechanism Cochrane describes:

• The government inherited a severely impaired central-bank balance sheet with a large stock of interest-bearing liabilities. In the initial phase it applied what the literature calls financial repression: negative real rates combined with capital controls. This contributed to a very significant reduction in the real value of the central bank’s interest-bearing peso liabilities.⁵

• Those liabilities were subsequently migrated to Treasury instruments—LECAPs, LEFIs, and related securities—placing responsibility for their financial cost on the Treasury. The primary surplus provided the fiscal backing for that transition.⁶

• As sovereign risk compressed and inflation declined, nominal placement and rollover rates on peso debt fell significantly. Domestic financing also underwent a sharp initial compression in real yields under financial repression. The lower-interest-cost channel was visible in actual Treasury refinancing operations.⁷

• Year-on-year inflation fell from approximately 211 percent in December 2023 to 31.5 percent in December 2025.⁸

This process is not a recommendation of financial repression. Repression is costly, distortive, and politically fragile. It is the mechanism “by foul means.” But the experience supports the theoretical channel Cochrane emphasizes: when the future interest burden is reduced in a credible way—whether by eroding the real stock or by generating primary surpluses sufficient to support financing at lower rates—and that reduction is perceived as durable, the fiscal pressure behind inflation diminishes. The fiscal anchor dominates.

Cochrane’s interpretation of Argentina emphasizes the change in fiscal regime and the associated credibility, rather than a Volcker-style strategy of high real interest rates.³ That is precisely the dimension of the experience that his framework helps illuminate.

Policy Conclusion

The question Cochrane asks himself has an answer within his own analytical apparatus, enriched by Friedman and by the Argentine evidence.

Persistently lower rates—whether after shortening maturity or after pre-announcing them with sufficient lead time—can be disinflationary only if the path is sustainable. Sustainability depends on the complete fiscal path, including debt service, and on the credibility of that path. If the government can generate the necessary primary surpluses and the market believes it will do so, the rate cut is coherent, the fiscal channel of lower interest costs reinforces disinflation, and the outcome is superior. Conversely, if lower interest costs simply become an invitation to additional borrowing and spending, the fiscal support for the result disappears.¹

Cochrane asks the right question when he inquires what monetary policy should be given fiscal policy. His passing remark—“Maybe Bessent and Warsh are cleverly working together!”—points exactly to the need for coordination.¹ The Argentine experience is relevant here as well. The design of monetary and fiscal policy brought together the Treasury and the central bank under Economy Minister Luis Caputo and central-bank president Santiago Bausili. The policy sequence reflected a shared diagnosis: the anchor was fiscal, the central-bank balance sheet had to be repaired, interest-bearing liabilities had to be migrated to the Treasury, and lower financing costs had to be supported by fiscal consistency.⁵ ⁶ That technical coordination is the “fair-means” element of the mechanism Cochrane describes, distinct from the repression used in the initial adjustment.

The Argentine case shows why the mechanism matters. The policy objective should be to achieve it by fair means—sustained primary surpluses, credible commitment, and effective Treasury–central-bank coordination—rather than by relying on repression. On the question of sustainability, however, Argentina does not yet provide a definitive long-term answer. Here lies the real challenge: the credibility required to sustain the policies over time.

Cochrane is fully aware of this problem. In the follow-up, “More on lower rates,” he proposes pre-announcing a lower-rate path several years in advance as one possible way to avoid the short-run contrary movement. Yet Kevin Warsh—whom he mentions in the earlier post—is deeply skeptical of forward guidance. Warsh has warned that advance commitments can constrain policymakers’ ability to respond to changing circumstances and that economic forecasting remains uncertain.⁹ This creates a practical difficulty: a distant commitment is unlikely to reassure markets if policymakers themselves resist being bound by it. The credibility of a lower-rate path is built not merely by distant announcements, but by repeated consistency between fiscal and monetary policy in the present and the near future.

Cochrane is right to be wary of taking simple models too literally. But his own logic—both in “Reasons to Lower Rates” and in the follow-up, “More on lower rates”—combined with Friedman’s lesson on time and with the Argentine evidence, points to a clear conclusion: the question is not whether lower interest rates can help reduce inflation. The question is whether the fiscal and monetary authorities can sustainably and credibly—and in a coordinated fashion—maintain the required path. If they can, the mechanism offers a coherent policy option. If they cannot, the attempt will fail.

That is the answer to John’s question. It is in his own text, in Friedman, and in the facts.

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Notes

1. Cochrane’s interest-rate argument. John H. Cochrane, “Reasons to Lower Rates,” The Grumpy Economist, September 4, 2026, and the companion post, “More on lower rates.” The first post explicitly considers interest-rate changes without an offsetting change in primary surpluses, distinguishes the effects of long-term and overnight debt, and identifies lower debt-service costs as a source of fiscal relief. Its conclusion is conditional on the government not using that relief to embark on additional borrowing and spending. (Grumpy Economist)

2. Friedman’s presidential address. Milton Friedman, “The Role of Monetary Policy,” American Economic Review 58, no. 1 (March 1968): 1–17. The address was delivered on December 29, 1967. Friedman distinguishes the initial effects of monetary expansion on interest rates from its subsequent effects through income, prices, and inflation expectations. The connection to intertemporal fiscal consistency in this article is an interpretation through Cochrane’s framework, not a claim that Friedman presented the fiscal theory of the price level. (AEA)

3. Cochrane on Argentina. Interview with Jorge Fontevecchia, Periodismo Puro, broadcast by Canal Net on February 8, 2026. The broadcaster’s account records Cochrane’s emphasis on the change in fiscal expectations and the absence of a preceding high-interest-rate stabilization. His views are paraphrased here rather than presented as a verbatim English quotation. (Net tv | Aire Fresco)

4. Fiscal balances and the size of the adjustment. IMF, Argentina: First Review Under the Extended Arrangement Under the Extended Fund Facility, Country Report No. 25/219, August 2025, Table 3b, “Federal Government Operations, 2023–30,” p. 40. The primary balance improved from −2.8 to +1.8 percent of GDP; the overall balance improved from −5.0 to +0.3 percent. The improvements of 4.6 and 5.3 percentage points are calculated directly from those reported figures, using the same institutional coverage and reporting framework for both years.

5. Interest-bearing central-bank liabilities. BCRA, Monthly Monetary Report, December 2024, pp. 4–5. The report explicitly identifies negative real interest rates and changes in sterilization instruments as components of the initial adjustment. Figure 3.1.3 presents interest-bearing peso liabilities at constant prices and distinguishes BCRA liabilities from Treasury LEFIs held by banks. The article deliberately assigns no single percentage to the real reduction. (BCRA)

6. Transfer of the financing cost to the Treasury. BCRA statement of July 11, 2024, announcing the elimination of money creation arising from interest-bearing liabilities. It identifies the migration to Treasury debt as beginning in May 2024 and the discontinuation of the BCRA’s reverse-repo facility from July 22. It also states explicitly that the Treasury would assume the financing cost associated with the new LEFI arrangement. (BCRA)

7. Treasury refinancing costs, real yields, and sovereign risk. In the December 11, 2024 exchange of LECAP S31E5, the Finance Secretariat reported a weighted effective annual yield of 38.84 percent, compared with 90.12 percent at the original issuance—a reduction of 51.28 percentage points—alongside an extension of weighted average maturity of 0.55 years. Participation was 19.47 percent, so these results apply to the exchanged portion, not the entire debt stock. (Argentina)

For the initial compression in real financing costs, the same CER-indexed Treasury bond, T2X5, was placed at a yield over CER of +1.46 percent on November 28, 2023, and −15.95 percent on December 20, 2023. Both releases use the same annualized semiannual-yield convention. These are yields relative to CER indexation, not total nominal peso returns. (Argentina)

The BCRA’s Annual Report to Congress, 2024, p. 52, separately records a decline in Argentina’s EMBIG sovereign spread from nearly 1,900 basis points at end-2023 to around 630 at end-2024. It also reports generally declining nominal Treasury placement yields during 2024, while CER-linked yields moved from negative at the beginning of the year to positive in the second half. The initial compression in real yields and the subsequent decline in nominal rates should therefore be understood as distinct phases. (BCRA)

8. Inflation. INDEC, Consumer Price Index: National Coverage, December 2023, released January 11, 2024, and December 2025, released January 13, 2026. The exact December-to-December rates are 211.4 percent for 2023 and 31.5 percent for 2025. The former is rounded to approximately 211 percent in the text. Both figures measure year-on-year national consumer-price inflation, not annual-average inflation. (INDEC)

9. Warsh on forward guidance. Kevin Warsh, “In Our Time,” remarks at the Jackson Hole Economic Policy Symposium, August 28, 2026, particularly the section “Forward Guidance and Its Stand-ins.” Warsh argues for limiting forward guidance in normal times, warns against overcommitting to future decisions, and emphasizes the limitations of forecasting. The implications drawn here for the credibility of a distant lower-rate commitment are the author’s interpretation. (federalreserve.gov)