Leaders from Ukraine, Poland and Baltics

The presidents of Ukraine, the Baltic nations and Poland are meeting in Warsaw on Monday to mark the 230th anniversary of their joint constitution, Europe’s first such written democratic document.

The neighbouring nations were one single state at that time.

The 1791 Constitution was intended to strengthen the country's political system and rule of law and protect it against aggression from neighbouring powers, including Russia.

Lithuania's president Gitanas Nauseda said Monday that his country will never accept Russia's 2014 annexation of Crimea from Ukraine and Moscow's military pressure on eastern Ukraine, or the Kremlin's attempts to influence Belarus.

“Lithuania will never recognise the illegal annexation of Crimea and will be taking steps toward ending the actual occupation of part of eastern Ukraine,” Nauseda said. “Whatever happens, we cannot allow Ukraine to slide back into the past.”

Ukrainian President Volodymyr Zelenskyy is due to hold talks with his Polish counterpart, Andrzej Duda, at a time of intensified conflict with Russia and tensions in eastern Ukraine.

Also attending the Constitution Day ceremonies are the presidents of Latvia and Estonia, countries on the European Union’s border with Russia and Belarus. They are scheduled to hold a televised debate.

AND OTHER , The first one hundred years of Northern Ireland's existence is ending as it began - with violence on the streets of Belfast and unionism in crisis.

The Belfast riots from 1920 to 1922 - known by some as the first Troubles - were a knee-jerk reaction by loyalists troubled by the raging guerrilla war against the UK and the perceived threat of being wrenched away from its bosom by southern nationalists.

For some, history appears to be repeating itself in 2021.

Just weeks after some of the worst rioting in the capital for years, the first minister and Democratic Unionist Party (DUP) leader Arlene Foster announced her resignation on Wednesday after a revolt against her continued leadership by the party's rank and file.

"The future of unionism and Northern Ireland will not be found in division," Foster said in her resignation address. "It will only be found in sharing this place we are all privileged to call home".

Despite her conciliatory tone, unionism continues to tear itself asunder as it grapples with the direct challenges to its core principles wrought by Brexit and an infamous clause in the UK-EU trade deal at the heart of the current polemic, the Northern Ireland Protocol.

But while the UK's departure from the European Union has been widely cited as the root cause of the latest upheaval in Northern Ireland, it's just another convulsion brought on by a deep-seated social malaise that unionist leaders have been unable to prescribe a remedy for.

In the country's centenary year, with unionism losing its footing on increasingly unstable ground, is it time for all those with a stake in its future to begin planning for the reunification of Ireland?

The path towards a united Ireland

On the face of it, is a difficult question to answer, not least because the past century has known so few years without bloodshed, sectarian violence or political rancour.

"Northern Ireland had a cruel birth," wrote Northern Irish poet and novelist Seamus Deane on the partition of the island in 1921 following the Irish War of Independence.

The cleaving of six countries in the predominantly Protestant, unionist province of Ulster from the Catholic, nationalist southern provinces ultimately sowed the seeds of the ethno-nationalist violence which was later to be reaped during the Troubles.

Now finding themselves in a majoritarian Protestant country, Catholics were soon the subject of microaggressions as well as discrimination for jobs and housing. Communities became segregated along sectarian lines, which in places like Belfast still remains in place with order between the two maintained by dividing Peace Walls.

While the historic Good Friday Agreement - brokered by political leaders of all stripes in Northern Ireland, the US, UK and Ireland in 1998 - removed the gun from Northern Irish politics, it has not yet wholly resolved more than a century's discord and division.

There is however evidence that seismic demographic shifts are taking place in Northern Irish society which are putting the country's place in the Union on the table for debate.

In an opinion poll published in January by the Sunday Times, more than half of respondents said they wanted a referendum on unity within five years.

While the majority of those still favoured to stay part of the UK on 47 per cent compared to those who backed a united Ireland on 42 per cent, a crucial 11 per cent were undecided on the issue.

It's this grey area that is sparking debate on the country's future.

"There can be no question that people are openly discussing the constitutional question like never before," Emma DeSouza, a political commentator and prominent civil rights campaigner in Northern Ireland, told Euronews.

"And I think that stems from the fact that Brexit and all of its outworkings are being rolled out against the wishes of the majority of the people of Northern Ireland".

The DUP under Foster's leadership was the only party in Northern Ireland to actively campaign for Brexit in the EU referendum campaign. In its aftermath, the party entered into a supply and confidence agreement with then-prime minister Theresa May following the 2017 general election.

However, Boris Johnson's final deal with Brussels (which was not supported by the DUP or any other Northern Irish political party) has been a particularly bitter pill for many loyalists to swallow, not least because of the imposition of new customs checks on trade between the UK and Northern Ireland.

The presence of a de facto border in the Irish Sea between the rest of the UK and Northern Ireland has inflamed the anger of unionists who feel betrayed by the government in London and the DUP. So much so, earlier this year there had been threats of violence made against port workers as well as legal challenges launched against the protocol by the DUP.

"Instead of negotiating a soft Brexit that takes into account our delicate peace process and the democratic wishes of the people of Northern Ireland, the DUP used its position to say no to every option on the table, leaving us with the NI protocol," contends DeSouza.

For her, having successfully fought a five-year-long battle with the UK Home Office to secure her rights to identify as Irish as ascribed to her under the terms of the Good Friday Agreement, any future decision will be made on the basis of equality and continued peace.

"In terms of the constitutional future, I believe much in the same vein as Germany, reunification is now an unstoppable force," she said.

"The gains of the peace process mean that identity lines have been softened. Unionism no longer holds a majority in Northern Ireland.