The current general election campaign has led to unprecedented political alliances which could -- by default or design -- reshape the future of the province and its place in the United Kingdom.

On Thursday, Northern Ireland, like the rest of the UK, will go to vote in the most important election in modern British history and as many as eight of the province's 18 seats may change hands.

In Belfast, London is either loved or loathed, depending which side of the community you sit on. Historically the divide ran along Protestant and Catholic lines, but in Prime Minister Boris Johnson's short few months in office he's inadvertently managed to bring that fence down. Now pretty much everyone in the city is against London in one way or another.

Indeed, it took only one night to turn what had been a tight partnership since the 2017 election -- that between Johnson and Northern Ireland's Democratic Unionist Party -- into rejection when the Prime Minister pressed ahead with his Brexit deal with the European Union against their wishes.

Until that moment, the 10 pro-leave DUP votes in Westminster counted for something. Then suddenly, according to Johnson's new calculus, they didn't.

Northern Ireland's eight other MPs were all remain supporters, but to Johnson's good fortune only one of them, the Independent Sylvia Hermon, took her seat. The others were all members of Sinn Fein -- Irish nationalists who refuse to swear allegiance to the British monarch and therefore don't take their seats in Westminster. This meant their pro-remain votes were never used against Johnson.

In Unionist neighborhoods in Belfast, election posters proclaim Johnson a betrayer. It is this perception which has turned the election in Northern Ireland on its head.

With Brexit looming so large over the election in Northern Ireland, it's hardly surprising that the general election is being seen here through a for- or against-Brexit prism.

In the Belfast North constituency, the Green Party and the moderate nationalist Social Democratic and Labour Party (SDLP) are not putting up candidates to avoid splitting the remain vote. This strategy gives Sinn Fein's John Finucane -- the dominant nationalist force in the constituency -- the best shot of beating long-time DUP incumbent Nigel Dodds.

This cross-party effort to defeat Dodds, the DUP's leader in Westminster, has led to old sectarian grievances being dug up. Hard-line unionists, or loyalists, are accusing the moderate nationalist SDLP of backing terror because of their support for Sinn Fein, a party historically associated with the Irish Republican Army (IRA).

DUP deputy leader Nigel Dodds at the party's manifesto launch.

This election, just like Brexit and all that's come with it, has dredged up memories of a bygone era in Northern Ireland that most people hoped had been left behind more than 20 years after the Good Friday Agreement was signed.

The perceived stakes in the election means that Northern Ireland's most hardcore loyalists are digging up every sectarian trope they can find. They fear that any nationalist gains in the election -- coupled with a Prime Minister in London who they believe is indifferent to their position -- will ultimately lead to a united Ireland. In the Belfast North race, this fear has led to John Finucane being smeared and accused of having former terrorists on his campaign.

For many reasons Finucane's name is a lightning rod for loyalists. Finucane is a lawyer and the lord mayor of Belfast. His father, Pat Finucane, also a lawyer, was murdered in 1989 by loyalist paramilitaries. Many in Belfast believe his killers had help from British forces. And in 2012, the then Prime Minister David Cameron apologized to Finucane's family in Parliament although he never specified for what and never admitted government guilt.

That loyalists would target John Finucane in this way is about as close as it is possible to come to putting crosshairs on his back without raising a weapon. Finucane's campaign has asked the police to investigate.

All of this creates a two-fold problem for the DUP, the natural party of choice for loyalist voters. One: the DUP overestimated its importance to Johnson. And two: If Johnson continues to ignore them and gets a majority the party becomes an irrelevance, so they are campaigning on what is essentially a "give us a 'second shot'" ticket.

Jim Wells, a veteran DUP politician explains it this way, "Vote us back to Westminster and we will persuade the PM he was wrong."

But that only works if Johnson cares -- which is directly tied to whether or not he needs their votes when polls close on December 12.

Johnson claims his Brexit deal is great for Northern Ireland and the Unionists, but Unionists fear the Brexit deal compromise "puts a border down the Irish Sea" and they will become a lesser part of the UK because of it.

It is anathema to a population that prides itself on centuries of loyalty to the crown and an identity built on ties across the water, not up and down their own isle.

The DUP's main political rival, the Ulster Unionist Party (UUP), is campaigning on a remain ticket.

Former naval commander Steve Aiken, who heads the UUP, says the only option for Unionists right now it to remain in the EU.

"I want to stop Boris Johnson's withdrawal deal, and the only way we can do that is by remaining in the EU," he told CNN.

And this is where we are: Unionism is now divided, split across Brexit lines.

Demonstrators from 'Border Communities Against Brexit' attend an anti-Brexit protest at the border between Dundalk, Ireland, and Newry, Northern Ireland.

In Belfast North the moderate UUP is not putting up any candidate -- a move many in the area believe is the result of loyalist intimidation -- giving the DUP's Dodds a better shot at collecting Unionist votes.

Bizarrely, in an indication of just how out of the ordinary these elections are, that could actually work against the DUP. Without another Unionist candidate on the ballot to vote for, UUP "remainers" could be tempted to back the pro-remain Finucane.

Admittedly, it would be an odd thing for any unionist to lend their vote to the pro-united Ireland Sinn Fein. Voting across sectarian lines is rare, but Finucane will be the only remain candidate in North Belfast with a shot at winning.

In Belfast South, Sinn Fein are paying the SDLP back for their help against Dodds by standing aside so the pro-remain SDLP candidate Claire Hanna, who has the best chance to beat the DUP incumbent there, can get Sinn Fein votes too.

The consequence of this could be even more significant than Finucane beating Dodds, since -- unlike Sinn Fein -- the SDLP take their seats in Westminster, meaning an extra pro-remain vote would come in to the Westminster mix.

Across the province other constituencies could also see unexpected results.

In Foyle, the most pro-remain constituency in the UK, where 81% voted to stay in the EU, Sinn Fein will face a stiff challenge from the SDLP.

In Belfast East, the remain-leaning moderate Alliance Party may beat the DUP, which would add another remain vote to the Westminster benches. On the other side of the equation, hard-line unionists may take Sylvia Hermon's seat in North Down; the independent has announced she won't stand again in the mostly middle class unionist area.

To the west along the border with the Republic of Ireland -- where Unionist farmers rely on an open, tariff free border -- the UUP is going head-to-head with Sinn Fein in Fermanagh and South Tyrone after the DUP candidate stood down.

These election shenanigans are unprecedented but they may not matter a jot on election night if Johnson and his party win a big enough majority.

Opinion polls currently forecast that the Prime Minister's party will win enough seats to confirm his Brexit deal and leave the European Union on January 31 as scheduled. At that point whether we see two extra remain or two leave MPs elected in Northern Ireland will make no difference in Westminster.

In that scenario Johnson and his Conservative Party might think the province can fall down their list of priorities, but that would be a mistake. A Brexit that Unionists and more hardline loyalists feel is thrust on them against their interests will likely prompt a fierce and potentially violent backlash.

Of course, if the polls are incorrect, the seats in Northern Ireland could have a big impact on Johnson's ability to pass his Brexit deal, and the price he'll pay for his abandoning of his erstwhile allies could be a very high one indeed.

On Northern Ireland, as has been the case over many decades, there are no easy options or simple outcomes. This election in that regard will be no different.

This story has been updated to clarify the issues in the Fermanagh and South Tyrone constituency.