New senior national correspondent John Roberts made his first appearance on CNN this afternoon with a report on the port controversy during The Situation Room.

But what is Roberts really doing at CNN? An e-mailer speculates:

"There was some talk a few weeks ago about why John Roberts would move from such a high-profile position at CBS to CNN. My guess is that CNN might be thinking about creating a single half- or one-hour flagship news broadcast at maybe... 7 p.m.? Right now, I learn so much more when I watch a single half-hour network evening newscast like than any half-hour of CNN -- the network broadcast is simply so highly produced and doesn't rely on chatter between anchors and reporters. CNN now has a relatively famous anchor with a high degree of gravitas; if they use the network's global resources to create a no-crap, highly produced weekday evening news broadcast, CNN could have itself a heck of a show."