Any new constitution would demand Assad step down which he has no intention on doing, he doesn't even have a choice anymore because its either arrest, a show trial and execution back home or being sent into exile and that means being put on trial in an international court. Right now Assad is president and he controls the army so he still hopes if he can beat them into submission. He is going to stop people coming out to vote on this constitution by scaring people into staying at home. The next 48 hours are probably going to be very bloody ones.
In Cameroon, suicide bombing toll rises to 19 dead, 143 wounded (Reuters)
from the article: Violence rages across Syria on eve of constitution vote