If it were just testing the waters --- why would the WH and Sestak avoid answering the inquiries for the past 2 months? It sounds as if this will require subpoena's and an "under oath" discussion where Sestak will either come clean and provide all he knows (doubtful) or he'll simply say he was mistaken and the dozen or so interviews where he stated "honestly, YES" the White House offered him something to drop out of the PA race, was all a big mistake (more likely). And if there's something found to implicate the WH in any way --- Sestak will take full blame and leave in disgrace taking the bullet for his party and President (somewhat likely depending on where this goes).
I just happen to feel that this would be a field day of giddy joy were this Bush/Cheney on the hot seat. The calls for Republicans to be jailed, impeached, etc... would be overwhelming. Somehow I don't see that same thing happening over the last 2 months.