Belfast - Northern Ireland began voting on Thursday in snap elections to resolve a political crisis fuelled by bad blood and Brexit, which is testing the delicate peace in the British province.Long-simmering tensions boiled over in January when the Sinn Fein party - once the political arm of the Irish Republican Army - brought down the province's semi-autonomous government.That triggered new elections to the Northern Ireland Assembly, a legislature in Belfast in which representatives of once warring communities have shared power on and off since a 1998 peace deal.More pessimisticObservers predict a similar outcome to the May 2016 elections, in which the conservative and pro-British Democratic Unionist Party won slightly more seats than the socialist and pro-Irish republican Sinn Fein.If the two parties cannot resolve their differences within three weeks of the vote, the assembly's executive could be suspended and the province fully governed from London."I'd be more pessimistic than optimistic that the DUP and Sinn Fein can get back in a government together quickly," said Jonathan Tonge, a Northern Ireland politics expert at Liverpool University.Martin McGuinness, a former IRA commander who became the deputy first minister of Northern Ireland, resigned in January in protest over a botched green energy subsidy scheme.It had been instigated by First Minister Arlene Foster, head of the DUP, when she was economy minister.Deeply engrained historical enmity was also exacerbated by the June vote for Britain to leave the European Union, which the DUP supported but Sinn Fein opposed.McGuinness is not standing again due to ill health and his successor as Sinn Fein's leader in Northern Ireland, Michelle O'Neill, has signalled a possible way out."We're up for going back into government but only on the basis of equality, respect and integrity," she said."We cannot go into government with Arlene Foster as first or deputy first minister while there is a shadow hanging over her, but that doesn't mean we can't find a way forward."Revived memoriesFoster has appealed for unionists to resist Sinn Fein's demands for her to stand aside pending an investigation into the energy scheme."If you feed a crocodile it will keep coming back for more," she told a party rally.In the streets of Belfast, there was disillusionment over the scandal.Prime Minister Theresa May has said Britain will leave the EU's single market and likely the customs union after Brexit, which would make the border between Northern Ireland and the Republic of Ireland the only land border with the European Union.The possibility of a return to border checkpoints has revived memories of "The Troubles", three decades of strife over British control of Northern Ireland in which more than 3 500 people were killed.Sinn Fein's leader in Ireland, Gerry Adams, has described Brexit as a "hostile action" by the British government, which would have a "negative impact" on peace agreement in Northern Ireland.