How can the Fed enforce exit criteria if they begin yield curve control?

Question

Over the past year, the notion yield curve control has resurfaced and appeared on FOMC minutes, decades after its last implementation.

According to the Fed's introduction page:

As the U.S. continued to incur debt, the Fed was obligated to keep buying securities to maintain the targeted rates—forfeiting some control of its balance sheet and the money stock. The public generally preferred to hold higher-yielding, longer-term bonds. Consequently, the Fed purchased a large amount of short-term bills, which also increased the money supply, to maintain the low interest rate peg.

After the war ended, FOMC members grew more concerned with addressing the rapid inflation that materialized. However, President Harry S. Truman and his treasury secretary still favored a policy that maintained YCC (which also protected the value of wartime bonds by implying a price floor). By 1947, inflation was over 17%, as measured by the year-over-year percent change in the consumer price index (CPI), so the Fed ended the peg on short-term rates in an attempt to combat developing inflationary pressures.)

This poses an interesting dilemma in configuring the bounds of the program. WW2 was a one-sided victory with rather clear end date. Yet the fact that YCC continued post-WW2 suggests that terminating the program was difficult. It's conceivable that marshaling the political will to end a program that the treasury likely derives massive utility for operating against a high fiscal-deficit backdrop was a major challenge. This phenomenon is sometimes termed "fiscal dominance."

A BIS paper goes into great length on the matter. Condensing one of the themes:

For many, a long period of large fiscal deficits and very high public debt-to-GDP ratios raises the spectre of fiscal dominance. It will in any case accentuate the links between fiscal policy, monetary policy and government debt management.

Question

How can the Fed enforce exit criteria without a massive/dramatic macro impairment (such as double-digit inflation)?

Answer 1

History and Theories of Yield Curve Control (20 pages)

https://www.boj.or.jp/en/announcements/press/koen_2017/data/ko170111a1.pdf

Lastly, as the fourth issue, I would like to touch upon the relation between fiscal management and yield curve control. As I noted, yield curve control by the Bank differs from the government bond price-supporting policies once implemented in the United Kingdom and the United States. While these policies aimed to minimize financial costs of the government, the Bank's current policy aims to overcome deflation and achieve the price stability target. Given that the policy directly sets the long-term interest rates as its operational target, however, it is undeniable that the area deeply related to fiscal management expands. Not surprisingly, therefore, there are voices of concern and criticism that the current policy coincides with money finance or monetization, or that the exit strategy of the policy will be constrained by consideration for fiscal management. It is therefore important that the Bank, bearing in mind those voices as well, gain the understanding of the markets and the public by releasing more carefully than ever the information on the purpose and ways of thinking about monetary policy implementation.

Quantitative Easing: Entrance and Exit Strategies (16 pages)

https://files.stlouisfed.org/files/htdocs/publications/review/10/11/Blinder.pdf

Because many of the Fed’s unorthodox quantitative easing policies put taxpayer money at risk, these policies constituted quasi-fiscal operations — equivalent to investing government funds in risky assets.

I would argue that there was less spare capacity in the economies after World War 2 due to destruction of assets in many countries and due to wartime restrictions of consumption and investment. Also the household sector in the United States emerged with a relatively clean balance sheet where collateral assets were not saturated with private debt. By contrast the economies with QE today have spare production capacity and assets saturated with greater burden of private debt. I am not aware of any econometric series that compares the private debt to government debt. Rebel economist Steve Keen publishes some charts making these comparisons of private to public debt but I have not drilled down into his sources of data.