On St Patrick’s Day 1995, Bill Clinton courted controversy by shaking hands with Irish Republican leader Gerry Adams. A politician accused of past involvement in the Irish Republican Army, Adams was a key player in the Northern Irish peace process. As such, Clinton’s willingness to extend his hand was correct if no less controversial because of it. This year, it is the Irish Taoiseach (prime minister), Enda Kenny, who faces criticism for his St Patrick’s Day meeting with Donald Trump. There is no better sign of the topsy-turvy times in which we live.

Irish politicians’ annual St Patrick’s Day visit to the United States is, perhaps, the most peculiar entry in the American diplomatic calendar. While Ireland is awash with St Patrick’s Day parades – imagine the Rio carnival in the driving rain – the country’s political classes cross the Atlantic. There they drink Guinness with Irish-Americans, talk up Irish business and charm US investors. The Taoiseach traditionally leads this pecuniary pilgrimage, which culminates in the presentation of a bowl of shamrock at the White House.

This shamrock statecraft began in 1952, when Ireland’s ambassador to the United States presented the plant to officials in the Truman administration. Then, this act sought to soothe anti-Irish feelings in the United States, born of Ireland’s neutrality in World War II. Now, it symbolizes the country’s high standing among Americans, who rate Ireland as a staunch ally. The bowl of shamrock is, more importantly, a low-cost diplomatic McGuffin that gives a small state disproportionate access to US policy-makers.

Enda Kenny is embattled. He successfully steered Ireland out of a deep recession and sovereign debt crisis to become one of the European Union’s fastest growing economies. But he has been criticized for the severity of budget cuts and for lacking empathy with those hardest hit by the crisis. His resignation appears imminent. However, such is the importance of St Patrick’s Day that Mr. Kenny has postponed an announcement on his political future until after he returns from the United States.

Meeting Mr Trump will not improve the Taoiseach’s popularity. A majority of Irish people view the Trump presidency as bad for Ireland. Nearly 40,000 people have signed a petition against Mr Kenny’s visit. Irish Americans, led by former Maryland Governor Martin O’Malley, have organized a #NoShamrocks campaign of their own.

Economics typically beats politics in such matters and Enda Kenny can ill afford to alienate the country’s most important trading partner after the European Union. Since 1990, Ireland has been the number one destination for US overseas investment thanks, in part, to the low rates of corporate tax levied by the Irish government. American tech-giants Facebook, Google and Twitter all have European headquarters in Ireland. The country’s low tax model is already under threat from the European Union. It could be further endangered if Donald Trump, as promised, delivers tax reforms that level the playing field for American companies.

If Enda Kenny must meet Donald Trump what should the Taoiseach say? Here are three political messages that might accompany the shamrock this year. Firstly, Mr Kenny should speak to Irish Americans in the Trump administration – Steve Bannon, Kellyanne Conway, and Sean Spicer among them – about the welcome received by their forebears who sought a better life in the United States. Secondly, Mr Kenny should speak for the 50,000 Irish people living illegally in the United States, highlighting their concerns – and the concerns of all migrants – over their place in a society to which they contribute so much. Finally, Mr Kenny should speak up about the threats posed to the peace process in Northern Ireland. Donald Trump has been quick to hail Brexit. He has been slow to consider how the United Kingdom’s departure from the European Union could impose a hard border between the north and south of Ireland that reawakens old enmities.

Dr Dermot Hodson (@dermot_hodson) is Reader in Political Economy at Birkbeck College, University of London.