This Saturday 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 take a comprehensive look at where the votes are going to come from in all three coming Democratic primary states, with an expert who knows each: From Pennsylvania, Democratic Rep. Jason Altmire; from Indiana, polling expert Fred Yang, of the Democratic firm Garin-Hart-Yang; and from North Carolina, Democratic Rep. and DNC member extraordinare David Price.

-- The NRCC faces problems, as everyone knows, but do GOP troubles this year signal a larger shift in the American political landscape? Rolling Stone associate editor Ben Wallace-Wells joins Politics Nation to chat about his mammoth must-read in this week's New York Times Magazine.

-- There's an open Senate seat and three open House seats. It hasn't given a presidential candidate more than a one-point win in twelve years. And John McCain chose the state to debut his first ad of the presidential cycle. David Drucker, of Roll Call, joins Politics Nation to take us through New Mexico, the Land of Political Enchantment.

All that and more, tomorrow 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.