Punjabi lobby, including general Kiyani, General Shuja Pasha (ISI Chief), PM Gilani (who is actually Siraiki but has aligned himself with the Punjabi establishment), Nawaz Sharif, Choudri Iftikhar, Imran Khan is very active in undermining PPP govt which they think has disproportinate Sindhi and Mahajar influence and is allied with ANP and is the foundation stone of threat to Punjabi domination in Pakistan.
Punjab has never tolerated any other province at position of power until it comes with approval from Punjab.
Nawaz Sharif with Saudi money and backing from Arabs (he has given one of his daughters in marriage to one of the low ranking Saudi royal families and is being backed by Wahabi lobby) is trying to dislodge Zardari who is backed by the West.
The Laywer movement was actually a Punjabi uprising against Musharaf who they thought was making compromises on Kashmir and Afghanistan, cutting down Punjabi influence in the state structures, and rewarding Mahajars.