As a prelude to negotiations supposedly with allies and trading partners, Donald Trump’s performance in the Rose Garden early last week will long be remembered, if only for the crass hyperbole. The United States has been “looted, pillaged, raped and plundered” he proclaimed, not by alien invaders from the Dark Planet but by, for example, Canada. A long list of countries identified as co-conspirators with the evil Canadians included Jordan, Cambodia and New Zealand.

The European Union had been established, back in the 1950s, “to screw the United States” and had managed to conceal its intentions for 70 years, deceiving every US president since Dwight Eisenhower. The list of territories on which unilateral tariffs are to be imposed includes the uninhabited Heard Island in the south Pacific and Diego Garcia, an island base occupied only by the US military in the Indian Ocean.

Trump’s principal accomplice in the Rose Garden was commerce secretary Howard Lutnick, who handed him the board on which the new, allegedly reciprocal, tariffs were inscribed. It had been expected that the new tariffs would reflect a calculation of the imposition on US exports to each country, including tariff and non-tariff barriers. This is a difficult calculation even for experts and there were none assisting Mr Lutnick.

The inquiring journalists were instead presented with a laughable document not based on trade barriers at all, but on the US trade deficit expressed as a percentage of the trade volume with the territory in question.

There is no basis in any version of international economics for these ridiculous calculations.

There are many economists in the United States who favour the Democrats, but quite a few who prefer the Republicans. Many of these are associated with the right-of-centre view that low tariffs and free trade are good for business, at one time a common position in the Republican party. The Democrats have traditionally been more partial to protectionism, defending US jobs against import competition and reflecting the party’s historical support base in the trade unions.

The outspoken adoption of protectionism by Trump exceeds anything contemplated by recent Democratic administrations and he platformed selected hard-hat auto workers in the Rose Garden. This has made things rather embarrassing for Republican-inclined economists trying to rationalise enthusiasm for Trump.

Some have given up, including erstwhile supporters in right-of-centre think-tanks including the influential American Enterprise Institute (AEI). Founded in 1962, the AEI has been well-regarded down the years even by political opponents and some of America’s top economists have served on its advisory committees.

Writing in the Financial Times last week, Michael Strain, the AEI’s director of economic policy, argued that Trump’s lurch to protectionism will not benefit its intended beneficiaries, the blue-collar employees in rust-belt industries. He concluded that liberation day will end up liberating Americans only from “the mercantilist fantasies of a deluded president”.

He also tweeted on X his dissatisfaction with the basis for the supposedly reciprocal tariffs brandished by Howard Lutnick, in the following terms: “This trade war is predicated on a mountain of bullshit.” Economists more partial to the Democrats have struggled to match Michael Strain for brevity.

Mr Lutnick is on firmer ground in his criticism of Ireland’s tax hospitality to US multinationals operating here. The US tax code indulges their willingness, perfectly legally, to pay taxes in Ireland which more properly belong in the United States. More importantly the remedy is in the hands of the US administration which could unilaterally bring the Irish revenue bonanza to an end, eliminating the budget surpluses which have emerged in recent years despite the surge in public spending and numerous tax give-aways.

Ministers face a threat to the public finances even if the tariff war fizzles out or gets negotiated away and, aside from finance minister Paschal Donohoe, appear to believe that its business as usual. There have been ministerial hints and even explicit promises that wage subsidies will be available for firms adversely affected by the 20% tariff applicable to all European Union countries.

The reality is that Ireland could face not just tariffs but also the disappearance of the budget surplus and with it the illusion that the public finances can sustain the economy through the repatriation of the unexpected corporation tax revenue to Washington.

Tánaiste Simon Harris spoke with Mr Lutnick last week and described their exchange as ‘constructive’. Since Ireland has no room for manoeuvre on common EU tariffs, on pharmaceuticals or anything else, and must share the fate of all EU member states, they can hardly have discussed trade. The only issue that arises between Ireland and the USA is the bonanza in corporation tax revenue.

The Americans can amend their corporate tax arrangements unilaterally and Mr Lutnick is alert to the possibilities. How come his talks with Harris were constructive?