This morning, from 10 a.m. to 12 noon Eastern, join Politics Nation on XM Radio's POTUS '08, when we'll tackle the week in politics. Listen free here (link about half-way down the page):

-- We talk to Mark Salter, one of John McCain's chief advisers, about the Arizona Senator's recent biography tour. Did McCain's trip through time get drowned out by Democratic squabbling? Did he make any real news?

-- Washington Post polling director Jon Cohen joins Politics Nation to chat about the state of the race, and all the latest polls. How can John McCain be tied or ahead when a generic Republican trails a generic Democrat by 15 points?

-- Voters in Louisiana head to the polls today to pick candidates for two special elections. If a certain Republican nominee wins his runoff, will the NRCC give up on the seat? A top Republican strategist and a Louisiana demographics guru give us the scoop, and Politics Nation's special weather correspondent will fill us in.

All that and more, this morning on Politics Nation, only on XM Radio's POTUS '08. Listen live, Saturday from 10 a.m. to noon Eastern and again at 7:00 p.m. Eastern.