Afghan presidential challenger Abdullah Abdullah plans to boycott next week's runoff against incumbent Hamid Karzai following a breakdown in talks on how to fix the country's electoral crisis, two people familiar with the discussions said. A boycott would severely undermine a vote intended to affirm the Afghan government's credibility. The political stalemate in Kabul comes as President Barack Obama has been meeting with his advisers to try to determine U.S. strategy in Afghanistan, including troop levels. A weakened Afghan government will make it harder for Obama to get public support for his efforts.