FOR anyone with a bias towards scientific rigour, pharmacies in continental Europe are liable to send blood pressure soaring. Many are gleaming white, high-priced temples to hypochondria, peddling cures for maladies not found in other lands (the French are obsessed with “heavy leg syndrome”, for instance). Worse, Euro-pharmacists often offer, unasked, remedies based on homeopathy: the bogus theory that some compounds, even toxins like arsenic, if so diluted that only a “memory” of their presence remains in a pill or potion, have magical curative powers. A European doctor offered Lexington a convincingly cynical explanation: because many clients are not very ill and “homeopathic” sugar pills are cheap to make, quack cures offer low risks and high profits.

Alas, a similar quackery increasingly infects politics across the Western world, and the side-effects are grave. Political leaders from America to Austria have a problem. To simplify, lots of people want something impossible: a return to some hazily-remembered golden era before globalisation, offering jobs for life, upward mobility and shared traditional values.

Too often, the response of mainstream leaders amounts to political homeopathy. They offer a small dose of a harmful idea, whether that is foreigner-bashing, protectionism or ugly partisanship, in the vain hope of soothing voters until their fevers pass. That is a mistake. What voters hear is leaders agreeing that economies should be shielded from global competition, that immigrants disproportionately steal jobs and property, or that political opponents are bent on wrecking the country. But then, to the disgust of supporters and grassroots activists, the realities of global commerce mean that those same leaders are only able to deliver half-remedies: eg, long-term targets for reducing immigration and vague pledges to put native workers first. Then such elites are surprised to find themselves barged aside by populist insurgents like Donald Trump peddling toxic ideas—build a border wall, start a trade war, ban Muslims—at full strength.

Republicans hold their national convention in Cleveland from July 18th-21st, at which they are due to make Mr Trump their presidential nominee. In a neat bit of timing the Republican majority leader of the Senate, Mitch McConnell of Kentucky, recently published a book of memoirs, “The Long Game”, explaining his philosophy of conservatism. An owlish, taciturn, supremely disciplined strategist—at one point his book describes a year and a half spent outwitting a Senate rival, ending with an assassin’s quiet boast: “Larry never saw it coming”—Mr McConnell is in many ways the anti-Trump.

That does not make Mr McConnell a centrist. Unlike Mr Trump, a would-be strongman who talks with relish of the president’s executive powers, the Senate leader returns time and again to what he considers his distinctively Republican distrust of government—reinforced by a brief stint at the Department of Justice, recalled as “people shuffling paper, doing the bare minimum, spending their days in an endless cycle of bureaucracy”. Mr McConnell praises the wisdom of the Founding Fathers in creating a Senate whose rules—requiring a super-majority to pass most laws—serve to temper the “worst impulses” of both politicians and the voters who put them there.

Mr McConnell, a senator since 1985, differs from Mr Trump in other ways. The Senate leader favours free-trade pacts and commends George W. Bush for keeping America safe after the September 2001 terrorist attacks. He praises Mr Bush’s belief that immigration is to be celebrated, not seen as a “problem to be solved”. He calls Mr Trump’s Muslim ban “a very bad idea”.

Chilly in public, the majority leader reveals a gentle side in his book, notably in a tribute to his mother. She nursed him through childhood polio, which enforced two years of painful bed rest. After his mother suffers a stroke in old age, the senator climbs onto her hospital bed and recalls how she lay beside him as a toddler, making towns out of toys on his blankets, transforming his small bed into a “nearly limitless world”. When she dies the next day, his sadness makes for hard reading. He describes his father’s belief in racial equality and “joy” at the passage of the Civil Rights Act—views which, he notes, were “extraordinary” for a man raised in the deep South. Mr McConnell scolds Barry Goldwater, the Republican presidential candidate in 1964, for opposing the civil-rights bill, a decision that “hurt our party for decades”.

Unsafe at any strength

Yet Mr McConnell has endorsed Mr Trump, a man willing to use racial, ethnic and religious resentment to win votes. Like other Republican grandees, he complains about conservative outside groups and talk-radio hosts who in 2013 forced a “futile” government shutdown. But this is the same Mr McConnell who accuses President Barack Obama of a “far-left” agenda to “Europeanise” America, and boasts that when Mr Obama pushed ideas “bad for the country”, such as his health-care reform law, Mr McConnell’s goal was to deny him a single Republican vote, to make it “obvious” which party was to blame. Small wonder that activists think they hear him declaring the Democrats a party unfit for bipartisan co-operation.

In an interview, Mr McConnell dismisses the suggestion that legislation like the Civil Rights Act passed only because in the 1960s the two parties were still broad and overlapping coalitions, and home to many centrists. When he was a child in the South, he says, “You couldn’t tell a Republican from a Democrat.” But now the two parties are “properly labelled” and “people pretty much know what they are voting for.” It is an elegant argument: modern hyper-partisanship as a source of democratic accountability. It is also unconvincing. Mr McConnell can distance himself from Mr Trump all he likes. But by peddling the poison of hyper-partisanship, even in controlled doses, he enabled his rise.