It has become a hallmark of the St. Patrick's Day holiday: the entire political elite of Ireland descending on the White House.Not this year. Northern Ireland's unity government is in turmoil, and its leaders are staying put in Belfast to try to resolve their troubles. At risk is an 8-year-old governing coalition of British Protestants and Irish Catholics that is supposed to ensure lasting peace in the British territory.First Minister Peter Robinson and Deputy First Minister Martin McGuinness spent Monday leading their parties in Belfast negotiations. Robinson's Democratic Unionists represent most Protestants, McGuinness' Sinn Fein most Catholics.Both parties said they were making unspecified progress in a process that, should it fail, would likely trigger the dissolution of the Northern Ireland Assembly for early elections that would leave any resurrection of power-sharing in doubt.The crisis stems from a surprise policy U-turn from Sinn Fein, which just before Christmas backed a compromise plan to cut welfare benefits, ending a budget dispute that had eroded the Northern Ireland government's ability to function. Publicly supportive of that deal, Sinn Fein last week stunned the Protestant side of the house by withdrawing support hours before a critical legislative vote on the cuts.While the White House has been hosting Northern Ireland leaders each St. Patrick's Day since the mid-1990s heyday of peacemaking, this time officials in the Obama administration sent a stern message to Belfast: Robinson and McGuinness should stay home unless they could come to Washington with a firm new agreement in place.Adding to the political tensions is a wave of accusations and counter-accusations involving the alleged cover-up of rape cases within the secretive ranks of Sinn Fein and the allied Irish Republican Army.Two people have accused Sinn Fein officials of warning them not to tell police of how IRA members raped them. One is a female relative of a senior IRA figure, the other a man who lived in a border home used as an IRA hideout.Sinn Fein which ended its official policy of hostility to the Northern Ireland police only in 2007 as a condition of entering the provincial government accepts that both were raped as teenagers in the 1990s, but rejects their cover-up accusations.Irish Prime Minister Enda Kenny will be guest of honor Tuesday at the White House for the Republic of Ireland leader's presentation of a bowl of shamrock to the U.S. president. That tradition dates to the 1950s and reached its apotheosis under former President Bill Clinton, the first American leader to take a hands-on approach to brokering peace in Northern Ireland.Kenny, while traveling over the weekend in Georgia and Texas, called on Sinn Fein to come clean about its involvement in shielding scores of perpetrators of rape and other crimes, including those committed during decades of IRA violence.Sinn Fein party leader Gerry Adams, also on the White House guest list for Tuesday, has accused Kenny of seeking to smear his reputation in advance of Republic of Ireland elections expected in 2016. Adams today is an opposition lawmaker in the Republic of Ireland where his party is rising high in opinion polls and aiming to take part in the next government.Adams had sharp words Monday for the U.S. government after his plans to meet State Department officials fell through in disputed circumstances. Adams, in New York, said he wanted a meeting but was being denied one and called the State Department decision "bizarre."His criticism appeared to get results as, hours later, Sinn Fein announced that Adams would meet a senior State Department official Tuesday.