Even if he does oversee a soft landing for the US economy, Fed Chair Jerome Powell will not deserve a place in the annals of history as the greatest central banker of all time. Not because bringing down inflation without causing a recession is as much a matter of luck as of skill — and economists will spend years debating how much of each Powell had — but because the mistakes the Fed made in 2021 will haunt the US economy for years to come. That alone takes Powell out of contention.

In the spring of 2020, as the world was in full pandemic panic and the US economy was in free-fall, the Federal Reserve turned to the emergency playbook from the financial crisis: It cut interest rates to zero and restarted quantitative easing, buying up longer-dated Treasuries and mortgage-backed securities, known as MBS. This time, however, it went much bigger — expanding its balance sheet to $8.9 trillion in 2022, compared to $2 trillion in 2009.

By the summer of 2020, even as many businesses were shut down, the housing and mortgage markets appeared to be functioning. And yet the Fed kept buying MBS. It did not begin tapering its purchases until November 2021, and did not stop buying new MBS until June 2022 — a full year after inflation took off, and years into a housing boom.

This, a recent economic research paper argues, is why mortgage rates were so low during the pandemic. In the early 2020s, the authors say, monetary policy juiced the housing market by lowering the spread on mortgages. Not only did the Fed buy MBS directly — at its peak it owned about a quarter of the MBS market — but its actions also increased the amount of MBS the banks bought. When policy rates fall to zero, banks attract more deposits, and they hedge that liability by buying assets that have a similar duration and risk characteristics.

With the banks and the Fed owning about half the MBS market, other investors became net sellers. The result was record-low mortgage rates and $8 trillion worth of mortgage originations in 2020 and 2021, as people bought homes and refinanced at the historically low rates.

Then, in 2021, inflation came back. In 2022, the Fed started increasing rates and stopped buying assets — known as quantitative tightening. Mortgage spreads shot up back up, and so did the cost of borrowing.

But because the US has 30-year fixed rate mortgages, many Americans are still benefiting from the low rates. More than half of homeowners now have mortgage rates below 4%. They will not be moving anytime soon. That means less inventory, so new buyers are facing higher prices to go with higher mortgage rates.

This is likely to remain the case for years — because odds are, mortgage rates will never return to pandemic levels.

I am normally not one to play Monday-morning quarterback. Making monetary policy is difficult, especially in extreme circumstances, and the pandemic was an unprecedented emergency. It may have made sense for the Fed to restart QE in the spring of 2020 when the outlook was so dire, though perhaps the QE was larger than it needed to be. But why did it keep buying MBS, in such large quantities, for another two years?

It didn’t make sense even then, as some critics noted at the time — it risked creating a bubble and distorted the housing market. Remember when there were bidding wars for houses in Boise, Idaho?

At this point, the best thing for the Fed to do is nothing. Eventually people will move, for all the various life reasons, and more homes will be built. But it will take years for the housing market to get back to normal. And if home prices stay high, there will be political pressure to bring mortgage rates back down below 4% — which would require more QE, which would further distort markets. Some Fed critics would then charge the Fed with acting outside its mandate, risking its independence.

I realize this is quite a parade of horribles, but it’s one Powell could have avoided had the Fed started to taper its MBS purchases at the end of 2020 or at least by early 2021. Instead, the Fed kept buying MBS long after the mortgage market recovered, and kept rates at zero for a full year after inflation took off.

This was a major policy error — and it takes Jay Powell out of any conversation about who is the greatest Fed chair ever. Paul Volcker can continue to rest in peace.

Allison Schrager is a Bloomberg Opinion columnist covering economics. A senior fellow at the Manhattan Institute, she is author of “An Economist Walks Into a Brothel: And Other Unexpected Places to Understand Risk.”