Frustrated by the persistence of large deficits, and alarmed by the long-term gap between spending and revenue, congressional Republicans are promoting a constitutional amendment to require balanced budgets.

The amendment has long been a popular idea. It is also a bad idea, which is why it’s a good thing it isn’t going to come close to being ratified.

There are several competing versions. Some Republicans favor the “clean” amendment they supported in the 1980s and 1990s, which just requires balance. Others fear this would lead to tax increases. They want an amendment that requires balance and also caps spending at 18 percent of gross domestic product and requires a two-thirds vote of Congress to raise taxes. That’s the version that all Senate Republicans have agreed to co-sponsor. Some House Republicans have mused about yet a third version, which would require the government to balance its budgets over the course of an economic cycle rather than in any year.