US reaction:Congressman Richard Neal, who chairs the Friends of Ireland in the US House of Representatives, said yesterday that the emergence of "what appears to be a two-party system" in the North places a new responsibility on Sinn Féin and the DUP.
"With the jubilation that comes from emerging victorious, there's also a heavier burden to govern. The other thing is I think the two-party system kind of builds in a shock absorber to the extent that there's no lurching.
"I think that's what two-party politics generally comes to mean," he told The Irish Times.
Mr Neal will lead a bipartisan, congressional delegation to the North next month that will meet the leaders of all the parties. He urged the DUP and Sinn Féin to move quickly to enter government and warned unionists that there would be no sympathy in Washington for any backsliding.
"I think it would be awfully short-sighted of Rev Paisley not to go into government. And I say that because I can assure everyone that there is a sense here that once Sinn Féin entered policing, no more excuses from unionism," he said.
Mr Neal said the US would continue to play a supportive role in the North as new institutions are established.
Former US senator George Mitchell, who chaired the talks that led to the Belfast Agreement, said he believed a powersharing deal following the elections is inevitable.
However, he confessed he did not think it would take this long to come to the point where he believed a deal would be possible.
He said all parties had "come a long way" and that Sinn Féin's decision to join policing boards was a "significant step".