KABUL, Afghanistan (Reuters) - Two influential U.S. senators who met Afghan leader Hamid Karzai warned Monday the ousted Taliban could return if the United States and other nations did not stay the course and help rebuild Afghanistan. The pair said Afghans were confident they could restore their war-battered land but feared the international community might go back on its vow not to desert Afghanistan now the Taliban and Osama bin Laden's al Qaeda had been defeated in the country. In the latest in a series of visits by key U.S. congress members, Sen. Robert Torricelli and Sen. Jon Corzine --...