Scott Bessent is discovering the limits of financial engineering. After doubling planned buybacks of long-dated Treasuries, the US Treasury Secretary is now promising a new fiscal initiative designed to address borrowing costs that have climbed to their highest levels in years. The sequence matters. Washington first tried to influence the bond market. It is now being forced back towards the problem the bond market is actually pricing: the deficit. The initial intervention worked. Thirty-year Treasury yields fell sharply after the Treasury announced larger purchases of securities with maturities between 10 and 30 years. The effect lasted less than a day. By Thursday, much of the rally had disappeared. That is the important signal. Besides, the dollar was not immune to this strategy.

Indeed, the dollar’s reaction was harder to ignore. It fell to a three-month low, while investors increased bearish positions against currencies including the euro and sterling. Some are beginning to see the currency as the natural pressure valve if Washington increasingly attempts to restrain long-term yields. That changes the debate. The Treasury can buy bonds. It can reduce long-duration issuance. It can finance more of the deficit through shorter-term bills. It can influence liquidity and force speculative positions to adjust. But it cannot abolish fiscal risk.

If investors believe the US should pay 5.3% to borrow for 30 years and Washington uses its balance sheet to push that rate lower, the risk does not disappear. The price through which investors express it may simply change. From bonds to currency. This is why the dollar may become the unintended casualty of Bessent’s strategy. Lower US long-term yields reduce the relative attraction of dollar assets. If those lower yields reflect improving inflation or stronger fiscal credibility, the effect on the currency need not be problematic. But if they result from deliberate intervention while deficits remain large, investors may conclude that Washington is effectively choosing a weaker currency over higher borrowing costs. That interpretation is already emerging in markets.

The contradiction is obvious. The administration says it supports a strong dollar. It also wants lower Treasury yields, cheaper mortgages, easier financial conditions, stronger exports and greater industrial competitiveness. It cannot necessarily have all of them simultaneously. A weaker dollar may even appear attractive politically. It supports exporters and makes American production more competitive. But the benefits come with costs. America remains a major importer. A weaker currency raises the dollar price of imported goods, commodities and industrial inputs. At a time when tariffs and energy prices are already adding inflation pressure, currency depreciation could reinforce precisely the inflation that keeps long-term yields elevated.

Washington could therefore enter an uncomfortable circle. Treasury yields rise because investors fear inflation and fiscal deterioration. The Treasury intervenes to push yields lower. The dollar weakens. A weaker dollar increases imported inflation. Inflation expectations become harder to contain. Bond investors demand higher yields again. Financial engineering then begins fighting the consequences of financial engineering. This is why Bessent’s promised fiscal initiative matters much more than another increase in buybacks. If Washington produces a credible reduction in future deficits, yields can decline for the right reason. Investors will require less compensation because the expected supply of debt and the associated fiscal risk have improved. But fraud reduction, tariff revenues, and assumptions about future AI-driven productivity are not yet part of a fiscal strategy. Public debt has already exceeded $40 trillion. The politically difficult spending categories remain healthcare, Social Security, defence and interest itself. Without meaningful action there or higher revenues elsewhere, the Treasury is largely managing the financing structure rather than changing the underlying arithmetic.

Bessent has said the government possesses a substantial toolkit. He is right. But every tool has a counterweight. Shorter issuance creates refinancing risk. Buybacks can suppress duration temporarily. Lower yields can weaken the dollar. And a weaker dollar can ultimately recreate the inflation pressure the intervention was designed to escape. The Treasury can influence where markets price America’s fiscal problem. It cannot prevent them from pricing it. If Washington does not want the adjustment in bond yields, it should be prepared for an increasingly uncomfortable possibility. The dollar may have to absorb it instead.