Sen. Hillary Clinton, D-N.Y., has all the hallmarks of a clearcut favorite to win the Democratic nomination for president in 2008. She enjoys nearly universal name recognition, focuses on high-profile issues and, perhaps most importantly, has the ability to raise a lot of cash. But there is a massive amount of ground to cover before she can allow visions of settling back into 1600 Pennsylvania Ave. to dance in her head. First up is her Senate reelection campaign. In a development that could spice up the 2006 race, two antiwar candidates have announced they will challenge Clinton for the Democratic...