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) as:

-- Have Democrats taken over the middle? And what happened to the once-mighty herds of Republican moderates? We'll talk to retiring Republicans Ray LaHood and Tom Davis to find out how the GOP can get its big tent back.

-- Barack Obama can win the South. Either that or Obama has no chance to pick up North Carolina, Georgia and anywhere else South of the Mason-Dixon line. We talk with UMBC Professor Thomas Schaller about Democrats' chances in previously Republican states.

-- And the Netroots Nation is meeting in Austin, Texas to plot strategy ahead of November's elections. Which matters more, the left's bloggers or the right's dittoheads? We'll get a live report from RCP's Kyle Trygstad in Austin.

All that and a few surprises, we're sure, 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 6:00 p.m. Eastern.