(CNN) -- As President Obama's second-term Cabinet starts to take shape, we can see some of the outlines of what the White House hopes to do in the next four years. 

The major theme is that Obama is prepared to defend his turf, tooth and nail. This is a Cabinet whose strength is defense rather than offense. 

Gone are the hopes of bipartisanship. Now it's time to really engage the partisan battle. Obama won't be pushing for many watershed changes in the next four years, but he is not going to make it easy for Republicans to make any deep inroads into what he has accomplished. 

During the last two weeks, the president rolled out his nominations on national security -- Sen. John Kerry for secretary of state, Sen. Chuck Hagel for secretary of defense, and John Brennan to direct the CIA. He then nominated his chief of staff, Jack Lew, to be secretary of the treasury. 

We must be careful not to infer too much from presidential appointments, since these people ultimately serve the interests of the president rather than vice versa -- but still, the identities of the members of the new Cabinet provide important hints. 

This is a team with experience and deep roots in Washington. It is clear that Obama, sobered after four brutal years of fighting with Republicans in Congress, realizes that he needs leaders who have clout in Congress. 

On national security, this is a team with deep experience that can protect the existing policies the administration has adopted. Obama has selected two Senate veterans who are also military veterans, Kerry and Hagel, with the hope of using their connections with legislators and their knowledge of the ways and means of the legislative process. 
Who's interests do these nominees serve?
of the president 