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):

-- Philadelphia Mayor Michael Nutter, the city executive in most demand this week, joins Politics Nation before he heads off to the Colbert Report on Monday. Nutter, who is backing Hillary Clinton, lays out the Pennsylvania landscape and talks about what he's hearing on the trail.

-- Former DNC chairman David Wilhelm, a super delegate backing Barack Obama, hits the airwaves to talk about his candidate's chances in the Keystone State, as well as Obama's thoughts on public financing and a potential delegate compromise in Michigan and Florida.

-- DCCC spokeswoman Jennifer Crider and NRCC spokesman Ken Spain head into Politics Nation Plaza to assess their respective party's chances in November. We promise we'll get beyond the spin and the canned quotes and get to the bottom of both parties' strengths and weaknesses.

All that plus Hotline Editor in Chief Amy Walter and South Carolina Republican Party executive director Jay W. Ragley, Saturday 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.