THE best way to prevent abortions is to prevent unwanted pregnancies. Family-planning clinics, which provide contraception, are good at that. In the past four decades they have helped slash America’s abortion rate. Yet this week President Donald Trump’s administration said it would begin the process of curbing abortions by cutting funding to some clinics. This is obviously self-defeating.

The administration plans to introduce a new rule under which clinics that provide abortions, as well as contraception, would lose federal funding through “Title X”, a federal grant programme for family-planning. The rule wouldn’t prevent federal money being used for abortions. That is already banned, in almost all cases, by the so-called Hyde Amendment, a measure that has been passed annually by Congress for the past 40 years. Instead, the administration means to cut Title X funding to any clinic that provides abortions—or even refers women to abortion providers.

The move is intended to fulfil one of Mr Trump’s campaign promises: to “defund” Planned Parenthood, an organisation that provides family planning services to about 40% of the 4m Americans covered by Title X. Because Planned Parenthood is also America’s biggest provider of abortions—about half its clinics perform terminations—conservative lawmakers have long called for it to be stripped of federal funds. Last year they tried to tie such a move to a failed effort to repeal Obamacare.

Pro-life campaigners, an important section of Mr Trump’s coalition, are cock-a-hoop. Marjorie Dannenfelser, the Roman Catholic president of the Susan B. Antony List, a pro-life campaign group, said the president had delivered, “on a key promise to pro-life voters who worked so hard to elect him”. But it is difficult to see who, in reality, this will benefit. It will certainly not be the 2.5m mostly-poor women who use Planned Parenthood’s services, which also include testing for STIs and cancer-screening. In some parts of America, groups that perform abortions are the only federally-funded providers of family-planning services.

Defunding Planned Parenthood won’t save money, either. The organisation’s provision of contraceptives prevent unwanted pregnancies, abortions and sexually-transmitted diseases, which are a lot more expensive to care for, carry out and treat than prophylactics. The Guttmacher Institute, an NGO, has estimated that for every public dollar spent on contraception, the government saves more than five dollars in Medicaid spending on pregnancies.

The administration knows this, of course. In a recently-published memoir, Cecile Richards, Planned Parenthood’s former president, described how Ivanka Trump, the president’s daughter, came to her with a proposal: if Planned Parenthood would stop providing abortions, the federal government would give it more funding. Planned Parenthood dismissed the idea.

Some conservative lawmakers, conceivably including Mr Trump, appear so sickened by Planned Parenthood’s record of providing abortions that they would do anything, however self-defeating, to close it down. Yet the main reason they have made it such a target is because they have few alternative means to satiate the pro-life demands of their voters—including around a quarter of Republicans who vote largely on the basis of this issue. Roe v Wade, the Supreme Court ruling that in 1973 established women’s right to an abortion, is unlikely to be overturned any time soon. A ban on abortion after 20 weeks, which made it through the House of Representatives, failed in the Senate. Mr Trump has been a champion of the pro-life cause since he became president, but has no serious prospect of ending abortion.

Of course, the new rule is likely energise those on the other side of the abortion debate too. Dawn Laguens, the executive vice-president of Planned Parenthood, which is likely to mount a legal challenge to the new rule, warned that it "would have devastating consequences across the country". Democrats, including an unusually large number of women candidates campaigning for the mid-terms, are already seizing on this. Senator Kirsten Gillibrand, a Democratic senator, told CNN that she expected it to “enrage the American public, particularly women, because it's an attack on them”.