Within hours it became clear that whoever does will have to fight to keep the U.K. from falling apart. Nicola Sturgeon, the leader in pro-E.U. Scotland, said she would push for a new independence referendum. A 2014 vote failed, but Sturgeon said a rerun of that contest was “highly likely” in order to protect Scotland’s place in Europe after English and Welsh voters overrode Scottish objections and opted for “out.” Nationalists in Northern Ireland – another area that favored remaining in the E.U. – echoed those calls, demanding a vote on Irish reunification.