Boris Johnson went a long way toward cementing his working majority in the U.K. Parliament with a visit to Northern Ireland on Wednesday, but did little to break the Brexit impasse with Dublin and Brussels.

The new prime minister met with the region’s main political parties in Belfast on the latest leg of a nationwide tour after taking office last week. He reiterated his plan to leave the European Union on Oct. 31 with or without a deal, while promising not to add infrastructure at the Irish border—the U.K.’s land frontier with the bloc—in any Brexit scenario.

Only the Democratic Unionist Party, which props up the government in Westminster, came out unequivocally in support of Johnson’s strategy. Leader Arlene Foster called it “sensible” and echoed his demand for a Brexit deal that both removes the backstop—a fallback provision in the agreement designed to keep the border with Ireland free of checks—and doesn’t “break up the United Kingdom.”

Johnson’s rejection of the backstop, a key element of the divorce deal his predecessor Theresa May negotiated with Brussels, has put the U.K. on a collision course with the EU and made a no-deal Brexit—the scenario most feared by businesses—more likely. The U.K. is due to leave the bloc in just three months’ time.

Border Problem

Johnson’s pledge not to add physical infrastructure on the Irish border, without offering a solution for how customs checks can be done, is particularly challenging to the Republic of Ireland and the EU. It puts the onus on them to find a solution to what will become an external frontier for the bloc’s single market, while likely souring any talks on a future trade deal.

Prime Minister Leo Varadkar said Ireland “isn’t going to be bullied” on the backstop and needs to stand firm. There is “total support” from the EU on the issue, he said in an interview with the Irish Mirror newspaper.

Johnson’s unwillingness to pursue a compromise on the backstop also triggered anger from his opponents in Northern Ireland. Sinn Fein President Mary Lou McDonald said Brexit is changing minds on the issue of a united Ireland, and called on the U.K. government to lay out what it sees as the threshold for a referendum on unification.

“If you are democratically intent on it, who are we to stop you?” McDonald said of Brexit on BBC Radio. “But you can’t wreck Ireland in the process.”

The Ulster Unionist Party, even though it opposes the backstop, also used a meeting with Johnson to raise its opposition to leaving the EU without a deal, the Belfast Telegraph reported, citing leader Robin Swann.

Reassuring Allies

The opposition of some of Northern Ireland’s parties won’t worry Johnson because he’s gained the approval for his “do or die” Brexit stance from the only one that matters in terms of votes in the Westminster Parliament—the DUP. Even a plunge in the pound hasn’t derailed that in the past few days.

“We are stepping up a gear and increasing the pace of our preparations as we get ready to leave the EU” on Oct. 31, Business Secretary Andrea Leadsom said in a statement after meeting executives from companies including General Electric, BAE Systems and Tate and Lyle Sugars in London.

Nevertheless, Johnson’s tour of the four U.K. nations—which he dubbed the “awesome foursome”—has not yielded wholly positive headlines. From boos in Edinburgh to a backlash from sheep farmers in Wales and calls for a united Ireland in Belfast, his promise to use Brexit to boost British unity looks a difficult challenge.