A judge at the High Court in Belfast has dismissed a legal challenge against a no-deal Brexit.
One of the three cases brought was by the victims' campaigner Raymond McCord who plans to appeal the decision.
The court heard arguments that a no-deal would have a negative effect on the peace process and endanger the Good Friday Agreement.
But the judge said the main aspects of the case were "inherently and unmistakeably political".
Lord Justice Bernard McCloskey also excluded a challenge against the suspension of Parliament because the issue formed the "centrepiece" of proceedings in England and Scotland.
The current five-week suspension of Parliament, a process known as proroguing, started in the early hours of Tuesday.
Analysis: Line drawn between politics and law
by Chris Page, BBC News Ireland correspondent
The judge's verdict, in essence, is that the matter he was asked to rule on should be dealt with by politicians, not the courts.
Lord Justice McCloskey said "virtually all of the assembled evidence belongs to the world of politics".
Raymond McCord says his legal team plans to appeal against the judgement. He expects the case to eventually go to Supreme Court - says it’s “important that Northern Ireland is represented”. pic.twitter.com/TrRRP3R3ix— Chris Page (@ChrisPageTV) September 12, 2019
But with the cases heard in England and Scotland heading towards the UK Supreme Court, Raymond McCord and his lawyers feel the issues related to Northern Ireland should be examined there too.
After Thursday morning's hearing, Mr McCord's solicitor Ciaran O'Hare said that in the absence of a Stormont Executive, the most important way Northern Ireland could have a voice was for people to take action through the courts.
A UK government appeal against the ruling will be heard by the Supreme Court in London next week.
Lord Justice Bernard McCloskey added that the courts had to "respect certain boundaries".
An appeal hearing is likely to be held on Friday.
Mr McCord's 22-year-old son, Raymond junior, was murdered by the UVF in Belfast in 1997.
No one has ever been convicted of the former RAF man's murder.