HOUSE Resolution 67, which Donald Trump signed last week, rolls back a rule that the Labor Department finalised late last year, which would have made it easier for cities and counties to run retirement savings plans for citizens who couldn’t get them through work. It is an odd choice for Republicans to kill plans that would encourage private, voluntary, tax-deferred saving, which they tend to approve of. But a trade group for investment funds opposes the city-run retirement plans. The Democrats on Capitol Hill, beset with other problems, are not picking a fight.

They should. The resolution itself is nothing more than a kick in the shins for the three cities, all run by Democrats, that had considered setting up plans—New York, Philadelphia and Seattle. But it points to a larger problem, which neither party has confronted. The United States has a retirement crisis, which it is treating like a savings crisis. They are not the same thing.

In traditional macroeconomics, all saving serves the same purpose: investment in the capital stock, or new machines to make stuff. Workers either spend from their paychecks on rent and food, or put money away in bonds, shares or savings accounts. Through the magic of capital markets, their savings both return interest and buy machines and tools—capital stock. In turn, this stock becomes component of the basic model for economic growth. These economic models consider only the aggregate sum of all savings: 100,000 funded pensions are worth the same as a single billion-dollar estate.

It is easy to conclude from economics textbooks that more saving is always and everywhere good. Paul Samuelson, the Nobel prizewinner from MIT who also tutored President Kennedy in 1960, wrote the dominant primer on macroeconomics for 20th-century undergraduates. In an edition from 1973, he explains the way countries form capital:

Two kinds of thrift are involved. First, people must resist the temptation to eat up some of the capital amassed in the past; they must “abstain” from consuming more than their current incomes… Second, if there is to be positive net capital formation, the community must usually undergo “waiting”—in the sense of giving up consumption goods now in return for more such goods in the future.

Mr. Samuelson does concede that a country might save so much that it drives down the value of what it has saved, reducing interest rates. But his language—thrift, resisting temptation, abstention—makes it clear that saving is a virtue. Greg Mankiw of Harvard, whose textbook on macroeconomics has replaced Samuelson’s, is even more explicit that there can be too much as well as too little saving. But when discussing what governments can do to change the savings rate, he proposes solutions that all increase it: higher taxes on consumption, for example, or lower taxes on capital gains. So what all policy-makers learned as undergraduates in 1975 or 1995 is that there could be too much capital in theory, but it is unlikely to be a problem that needs fixing.

There is, now, too much capital. Ben Bernanke, then chair of the Federal Reserve, first described a global savings glut in 2005. It is a well-studied and well-known phenomenon; here is Lawrence Summers of Harvard summing it up last year. And, as predicted in both Samuelson and Mankiw, there are not enough investments to accommodate the world's savings, and interest rates have dropped. Yields for both high-quality corporate bonds and long-term American federal debt are now lower than at any time since 1973 (see chart).