AT THE start of a new Congress everything seems possible. Republicans have spent much of 2015 on bucolic retreats, pondering how to remake America. One rather ambitious idea is to repair both the budget and the country by supporting marriage. Most mothers under 30 are not married to the fathers of their children. Pledging to take care of each other for richer, for poorer is more and more the preserve of college-educated folks for whom poverty is theoretical. Senators Marco Rubio and Mike Lee have a proposal to change child tax credits to promote marriage; Senator Tim Scott is interested too. Congresswoman Lynn Jenkins says that ending marriage penalties will be part of any tax reform proposals from the House.

When marriage is hitched to politics the result is usually muddled thinking. Social conservatives think that lax attitudes to sex, a decline in manliness, short skirts and a hundred other things have chipped away at a sacred institution. The Heritage Foundation, a think-tank with a “Marshall Plan for Marriage”, recently puffed a study suggesting that online pornography was the cause of the rot. People who reckon culture is to blame often propose economic solutions, from getting rid of marriage penalties to using public policy to promote wedlock. Thus some conservatives, who tend to assume that the government mucks up everything it tries, are nonetheless arguing that it can revive the traditional family. Leftish Democrats, meanwhile, think that marriage has been undermined by rising inequality, and especially the low wages of unskilled men, which make them less attractive as mates. They tend to argue that marriage, unlike practically every other social problem, cannot be fixed by government.

Both these views are confused. There are indeed marriage penalties in the tax code and in the welfare system: a single mother who marries a man with a job can lose all kinds of means-tested benefits. But there are also some marriage bonuses, and the tax code is so complicated that few Americans know whether tying the knot will mean they owe the taxman more or less. The federal government has made $114 billion-worth of pro-marriage fiddles to tax laws in the past decade with nothing much to show for it. And there is no evidence from decades of marriage-promotion programmes that the government can persuade people to get or stay hitched, a finding that will not surprise anyone who has ever actually been married.

As for the notion that inequality is to blame, that is muddled too. Most of the increase in income inequality has been at the very top of the scale: it is hard to see how the vast pay packet of a hedge-funder in New York changes the intentions of someone waiting tables in Utah. Though the wealthy are much more likely to wed than the poor, the relationship between money and vows is not clear-cut. Lots of people who decided to marry a few generations ago were poorer than those who choose not to today. Nor did marriage rates decline in the 1920s, when the surge in stock prices gilded the incomes of rich Americans. This tangle over inequality blinds Democrats to the possibility that causation may run in the opposite direction: that unwed parents raise poorer children. Isabel Sawhill of the Brookings Institution, a think-tank, calculates that returning marriage rates to their 1970 level would lower the child-poverty rate by a fifth. This omission may be deliberate: Democrats are reluctant to offend unmarried women, 60% of whom voted for the party’s candidates in 2014.

A debate about marriage should begin by acknowledging that the high rates of the 1950s and 1960s were a peak rather than the norm. The marriage rate in America has only recently dipped below where it was at the end of the 19th century, according to Andrew Cherlin of Johns Hopkins University. Reviving marriage rates of the 1950s, an era looked on fondly both by conservatives (who remember an America as wholesome as its cereal adverts) and by liberals (who recall an age when well-paid jobs were available for people with few qualifications) would require reviving some of that decade’s less jolly features too.

Shame and the single girl

First among them would be the glares of disapproval directed at loose women who had children before they were married. As late as the 1960s children thus brought into the world would have “illegitimate” stamped on their birth certificates. Many families were so ashamed of their unwed pregnant daughters that they were sent to places such as the Florence Crittenton homes, run by a charity founded to reform prostitutes, where they could give birth in secret and put their babies up for adoption: at least 25,000 mothers lost contact with their children this way every year.

Next on the list would be to bring back the huge difference between male and female wages that made marriage such a good financial bet for women. In the post-war years, an American working man could expect to double his earnings between the ages of 25 and 35, while women’s wages were flat, according to Stephanie Coontz, a historian of marriage. It is no coincidence that the decline in marriage has accompanied the improvement of women’s prospects in the workplace. It might be possible to increase the economic muscle of men relative to women, by giving tax breaks for possessing testicles, say, or discriminating in favour of men in college admissions. But it would be a terrible idea.

A stable, loving two-parent family may be the optimal way to raise children, but to mourn the retreat of marriage is also to regret two of the most welcome social changes of the past half-century. Those who would use the tax code to promote marriage “have a hard time putting themselves in someone else’s shoes”, says Adam Getz, a single father of two who helps to organise gatherings for single parents and their children in Virginia. Very few of the group wanted to be single, adds Mr Getz: in most cases singledom was forced upon them. Altering the tax code to the disadvantage of people like him will not change that.