A Cardiff pact has united SNP, Plaid Cymru and Sinn Féin around demands for self-determination and constitutional change.
Scotland wants independence, Sinn Féin seeks Irish reunification, while Wales is pushing for greater devolution.
The pact puts fresh pressure on Westminster but does not itself trigger an independence or reunification referendum.
The United Kingdom is facing renewed calls for constitutional change after political leaders from Scotland, Wales and Northern Ireland joined forces at a summit in Cardiff, putting fresh pressure on Westminster over the future of the union.
Leaders of the Scottish National Party (SNP), Plaid Cymru and Sinn Féin signed a memorandum of understanding on Monday calling for greater self-determination and constitutional change in Scotland, Wales and Northern Ireland. The agreement does not trigger a referendum or alter the constitutional status of Scotland, Wales or Northern Ireland. Instead, it brings together three nationalist movements whose demands have gained political momentum at a time when questions over devolution and the future of the UK are again becoming more prominent.
The three movements, however, are seeking different outcomes. The SNP wants Scottish independence, Sinn Féin supports Irish reunification, while Plaid Cymru is seeking greater powers for Wales and has kept independence as a longer-term possibility. The agreement represents political cooperation between movements pursuing different constitutional goals.
Why has the issue returned now?
The latest push follows Plaid Cymru's victory in May's Senedd elections, which means all three devolved governments now have first ministers from parties committed to constitutional change, alongside continuing disputes over the distribution of powers.
The Guardian reported that the Cardiff meeting brought together the leaders of the main nationalist parties in Scotland, Wales and Northern Ireland at a time when demands for greater autonomy have become more prominent. The parties argued that decisions about their constitutional futures should be determined by the people of Scotland, Wales and Northern Ireland rather than by Westminster.
Scotland's independence debate has continued since the 2014 referendum, when voters rejected independence. The issue has remained politically significant, particularly following Brexit, which Scotland voted against.
According to Al Jazeera, recent polling cited in its report put support for Scottish independence at 47%. The SNP has continued to argue that Scotland should have another opportunity to vote on independence.
Wales has taken a different political path. Plaid Cymru's stronger electoral performance has brought Welsh constitutional issues further into political debate. Al Jazeera cited polling showing support for Welsh independence at 32%, while the immediate political demand has also focused on securing greater powers for the Senedd.
Al Jazeera reported that a University of Liverpool survey found that 36% in Northern Ireland would vote for Irish reunification. The issue is also governed by arrangements established under the Good Friday Agreement, making Northern Ireland's constitutional process different from the independence debates in Scotland and Wales.
Scotland, Wales and Northern Ireland have different demands
Scotland has already held an independence referendum. In 2014, voters rejected independence, but the SNP has continued to campaign for another vote. Whether another referendum should take place has remained a source of tension between Edinburgh and Westminster.
AP reported that Burnham had initially said he would allow another Scottish independence referendum if there was a “clear consensus” in Scotland, but later wrote to Swinney saying a vote was “off limits”.
In Wales, the immediate focus is on greater devolution. Plaid Cymru has ruled out an independence referendum during its first term but continues to support Welsh self-determination. The Guardian reported that the party's recent electoral gains have strengthened the position of Welsh nationalists, although the political circumstances differ from those in Scotland.
Northern Ireland has its own route to a possible constitutional change. Sinn Féin's objective is not independence for Northern Ireland but reunification with the Republic of Ireland. Under the Good Friday Agreement, the British government must call a referendum if the UK secretary for Northern Ireland believes it is likely that a majority would vote for a united Ireland.
What does the Cardiff agreement mean for the UK?
The memorandum does not itself change the UK's constitutional structure.
Burnham's position puts him at odds with the nationalist parties, which say that constitutional questions cannot simply be set aside.
The memorandum gives the three movements a common position on the principle of self-determination. The parties have also expressed an interest in working together on issues including economic development, energy and relations with Europe, according to Al Jazeera.
But the agreement does not remove the political and constitutional obstacles facing each movement. Scotland would need Westminster's cooperation for another referendum, as happened with the 2014 vote. Wales does not have the same history of an independence referendum, while Northern Ireland's reunification question is subject to the specific provisions of the Good Friday Agreement.
For now, the agreement increases political pressure on Westminster over devolution, referendums and the UK's constitutional future.
The Cardiff summit has brought those separate demands into the same political conversation. Whether that leads to further constitutional change will depend on public support, future elections and Westminster's response.
