For anyone so interested, you can watch Sens. John McCain and Joe Lieberman outline the rationale for their plan by going to
the C-SPAN video page and clicking on the "Sen. McCain (R-AZ) and Sen. Lieberman (I-CT) on Iraq Troop Surge" link. The remarks are brief, with Sens. McCain and Lieberman each speaking for about 10 minutes.
The thrust of the plan is that given the situation on the ground, increased military forces are needed to allow the formation of a political solution in Iraq. The following quote is from Sen. McCain and begins around the 4:21 mark.
I believe that the war is still winnable, but to prevail we’ll need to do everything right and the Iraqis will have to do their part. And are we concerned about doing everything right and the Iraqis having to do their part? Of course we are.
There is agreement among most observers that the problems plaguing Iraq require a political solution. We all agree with that. But it's also a lesson of history that unless you have security – security is the necessary precondition for political progress and economic development.
I'd be interested in hearing from those that support a political solution but oppose a troop increase. Under what scenario do you see a political solution taking shape?