Three things ... I think ...
(1) Pointing out the surge in Arab voting
(2) Changing his position on a Palestinian State
(3) Telling the Nationalists that they ALL better vote for him or they were going to get the Zionist Union
AND ... doing all that in the last 24-48 hours before the election ... :-) ...
I agree with your reasons, but I credit backlash against obama’s active interference as a considerable factor as well.