Palestinian political instability

Israeli intelligence agencies: relations with Palestinian Authority damaged, any quiet will be short-term – Amos Harel – Haaretz 04.11.15
Israeli intelligence agencies say situation within Palestinian Authority — the weakened status of President Abbas, the emerging battle for his succession, and the sense of the PA’s diplomatic ineffectiveness — will not allow for the resumption of a long-term calm.
Read report here

And see:
With no diplomatic horizon, terror wave won’t break – Avi Issacharoff – The Times of Israel 03.11.15
Without a diplomatic process, any reduction in the pace of terror attacks will be temporary, and is likely to be followed by an even worse escalation.