Friction rises in Nigerian governmentJefferson case contributing to the tension Thursday, October 05, 2006 By Bruce Alpert WASHINGTON -- Imagine that President Bush and Vice President Dick Cheney were accusing each other of improprieties so bad that they called for impeachment proceedings. That bizarre scenario is akin to what is playing out in Nigeria, Africa's most populous country, as President Olusegun Obasanjo and Vice President Atiku Abubakar engage in a monumental political battle that got its impetus, at least in part, from the lengthy U.S. Justice Department probe of U.S. Rep. William Jefferson, D-New Orleans. There is concern within Nigeria...