HILLARY CLINTON was railing against Citizens United v Federal Elections Commission, the 2010 Supreme Court case lifting some campaign-finance regulations, even before Bernie Sanders declared he would run on a platform of severing the link between money and politics. The ruling, which permits corporations and unions to spend unlimited money in political campaigns as long as the funds are not routed directly to or coordinated with the candidates’ campaigns, has been a scourge of the left since it was announced. In his 2010 State of the Union address, Barack Obama lambasted the decision for “revers[ing] a century of law” and “open[ing] the floodgates for special interests, including foreign corporations, to spend without limit in our elections”. When Mr Obama offered this critique in the House chamber, Justice Samuel Alito could not contain himself. Deviating from the justices’ traditional poker-faced gaze, he shook his head and mouthed “that’s not true”. Technically speaking, Mr Alito was correct: the court’s decision left in place strict prohibitions on foreign spending in American elections. The Federal Election Campaign Act (FECA) bans campaign contributions from foreign nationals, governments, political parties and corporations, and makes it illegal for American citizens to help foreigners violate that rule. Citizens United did not meddle with these rules.

But in the six-plus years since the ruling was announced, many new, powerful spigots have opened spouting millions of dollars in campaign spending through Super PACs and politically invested non-profit groups—and some of those streams do seem to originate from abroad. In a detailed assessment of how Citizens United has altered the contours of campaign-finance in America, Jon Schwartz and Lee Fang, writers at The Intercept, have uncovered evidence of one such episode.

A wealthy Chinese couple living in Singapore, Gordon Tang and Huaidan Chen, own San Francisco-based American Pacific International Capital (APIC), a real-estate company. In the spring of 2015, APIC donated $1.3m to Right to Rise USA, a Super PAC supporting Jeb Bush’s ill-fated presidential campaign. As it happens, campaign contributions from foreign-held but American-based companies are perfectly legal as long as the owners have no role in directing the disbursement of the funds. But a memo Messrs Schwartz and Fang came across—dated February 19, 2015, weeks before the first APIC funds flowed to the Super PAC—suggests that the couple may have been actively involved in the decision to support Mr Bush. The memo came from Charlie Spies, a prominent Republican strategist and lawyer who was general counsel for Mr Bush’s Super PAC. Mr Spies outlined the state of the law to Right to Rise USA and explained that “the creation of a separate account of only US raised monies...would be sufficient to permit donations from a domestic subsidiary directly to a Super PAC”. It’s rather uncanny that only a month later Right to Rise USA cashed a big check from APIC—which, incidentally, claims Neil Bush, Jeb’s brother, as a board member.

The upshot of this story is not that APIC’s owners necessarily did anything illegal—although they may have. The moral is that by permitting outside organisations to spend as much as they like to elect the candidates they prefer, Citizens United has ushered untold waves of cash into the political process and, apparently, enabled foreigners to slip through legal loopholes and insert themselves into America’s political battles. Some commentators, like Theodore Kupfer at the National Review,dismiss the well-documented surge in campaign spending as nothing to worry about. The $27-at-a-time success of Bernie Sanders, and the dismal showings of well-financed candidates like Jeb Bush and Marco Rubio prove, he writes, that “independent expenditures on political campaigns do not pose a threat to the legitimacy of national elections”.

This dubious conclusion reads far too much into a few campaigns in one election cycle. Big money is still a fact of life in congressional races and it will undoubtedly return to the fore in 2020. In a bit of poetic justice, it seems likely Citizens United (which arose from a group seeking to discredit Hillary Clinton in her 2008 race) will help Mrs Clinton win the White House in November. She has raised nearly a third of her $375m in contributions from outside groups, while Donald Trump’s fundraising lags far behind. He has raised only about $91m, a mere 3% of which has come from sources liberated to spend freely in the wake of Citizens United.

While Mrs Clinton is enjoying the spoils of what she calls a “disaster for democracy”, she pledges to tear it down once in office. The goal is worthy, and her proposals to increase transparency and establish a federal matching programme for small donations are both promising and plausible. But her more ambitious plan is guaranteed to come up short. Consider first her promise to nominate Supreme Court justices who will overturn Citizens United. Litmus tests are dubious tools: many potential nominees will not have a record indicating how they would rule on the matter, and it is uncouth for a president or senator to ask (or for a nominee to answer) such direct questions. Even a bloc of justices fully committed to overturning Citizens United would be powerless to do so unless and until an appropriate case comes before them. Mrs Clinton also says she will (in her first 30 days in office) sponsor a constitutional amendment “to overturn Citizens United”. While she’s at it, she should push for an amendment abolishing Islamic State and calling for fairy dust to rain down over America. As president, amendments are not her call. Not at all. She would need two-thirds of both houses of Congress and three-quarters of the states to agree to such a change. The chances of that are about as strong as getting Donald Trump to close his Twitter account—or release his tax returns.