In the UK’s EU referendum debate, the Remain campaign can be thankful that the government has crisscrossed the country with a relentlessly positive message. The Irish government that is.

If the UK votes to leave the EU this week, UK Prime Minister David Cameron will be rightly criticized for a campaign designed to scare the electorate about the costs of Brexit rather than address their legitimate concerns about who governs the EU.

Not so his Irish counterpart, Enda Kenny, and other Irish politicians, who have been frequent visitors to the UK over the last year to talk up the economic and political case for remaining in the EU.

As polling day approaches, we might have expected the Irish government to withdraw from the British debate. It has done anything but.

At the end of last month, Kenny appeared at a sporting event in London to make a pro-EU pitch aimed at the 500,000 Irish people living in the UK who will have a vote in the referendum. Last week he was in Belfast talking about the risks from Brexit for Northern Ireland before making a visit to Liverpool.

Transnational politics of this sort is a rare occurrence in Europe. Goods and services cross borders freely but political debate remains resolutely national. Indeed, the British government reportedly urged Commission President Jean-Claude Juncker to stay quiet for fear that he would bolster the Leave campaign.

Juncker has not entirely heeded such advice. Asked about possible Brexit negotiations in an interview with Le Monde, the Commission President insisted that ‘deserters will not be welcomed back with open arms’.

This ill-judged comment was a boon to Nigel Farage. The UKIP leader was applauded when he replied to Juncker via a television audience: ‘We’re British we’re better than that, we’re not going to be bullied by anyone’.

What explains Ireland’s unusual foray into the political affairs of another EU member state and what can we learn from it?

The first and most obvious reason for Ireland’s involvement is that it has a great deal to lose from Brexit. The UK is a major trading partner for Ireland and some estimates suggest that bilateral trade flows between the two countries could fall by as much as a fifth if the UK were to leave the EU.

There are concerns too that Brexit could lead to the re-imposition of border controls between Ireland and Northern Ireland. This would hit cross-border trade and it could have broader political repercussions. The EU was not the most important player in the peace process by any means but the Good Friday Agreement is built on the idea of the UK and Ireland ‘as friendly neighbours and…partners in the European Union’.

Self-interest alone cannot explain Ireland’s deep involvement in the UK referendum debate. Other EU member states have much to lose from Brexit and yet their leaders have been taciturn.

German Chancellor Angela Merkel waited until the beginning of this month to make a few brief remarks about UK membership at a press conference in Berlin. Interventions from other EU member states have been equally perfunctory.

Barack Obama’s comments on the obstacles to a future US-UK trade deal, delivered during his visit to the UK in April, were much more effective. And yet, as an outsider to the EU, he was vulnerable to criticisms that he wanted Britain to stay in a kind of club that the US would never join.

Another important factor behind Irish involvement in the UK debate is that the Irish government has first hand experience of EU referendums. The nine European referendums held in Ireland since 1972 have revealed rising frustrations with political elites in Ireland and the EU. ‘No’ votes against the Nice Treaty in 2001 and Lisbon Treaty in 2008 were humbling experiences for the main political parties, which were outmaneuvered by grassroots movements and political populists.

Irish Foreign Minister Charlie Flanagan shared this experience in a speech at Chatham House in September of last year at a time when many in the UK were complacent about the referendum campaign to come. ‘In today’s busy world, in an era of Twitter, Snapchat and Facebook, how can one communicate the benefits of something as broad and deep as the EU?’ he asked.

A final driver of Ireland’s participation in the UK referendum debate is that Irish politicians understand what plays well in the British media. Kenny’s speeches combine blunt messages about the benefits of EU membership with an intergovernmental vision of European cooperation.

‘Britain and Ireland are more than neighbours; we are friends’, Kenny said in a speech in London in January. ‘ We are rivals at times of course. We compete on the global stage whether for economic investment or sporting success. Yet we work closely together within the European Union as like-minded colleagues’.

The lessons from Ireland’s involvement in the UK referendum campaign, though they could come too late to save British membership, are three-fold. Firstly, transnational politics is a possibility in Europe provided the message is well calibrated to the host country. Secondly, heads of state or government appear more adept at such politics, as things stand, than the leaders of supranational institutions. Thirdly, transnational politics works more effectively in person than through the prism of the media.

In short, political debate doesn’t need to stop at national borders but it requires savvy politicians to cross one of Europe’s most challenging political frontiers.

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