There is one bright spot in the December “termination for convenience” of the main contracting joint venture on the Boston area’s Green Line Extension light-rail project: No one is pointing fingers at the contractor as the key culprit behind the project’s soaring cost, which currently is $700 million to $1 billion over its roughly $2-billion budget. In fact, Peter S. White, the chief executive of J.F. White Contracting Co., the joint venture’s main partner, hopes to return to work on the project in the future.

More important, White defended the so-called construction manager/general contractor (CM/GC) method being used to build the 4.7-mile-long Green Line Extension. The approach allowed the Massachusetts Bay Transportation Authority (MBTA), the agency directing the project, to sequence the work in packages as the designs were developed, with input from the contractor.