are we more likely to deter the future use of chemical weapons by acting or not acting? >> the syrian government vows to defend itself by using all means. the regime has hundreds of tons of mustard gas and large stock piles of sarin plus 100,000 missiles and rockets. john, diana, it's not clear what assad will do if attacked. syria has missiles capable of reaching israel. the israeli prime minister says his country is ready. john, diana. tahman bradley in washington, thank you. it appears syria may already be responding to the threat of a u.s. strike. syrian electronic army, group of pro-assad hackers says it has taken control over several major media web sites including twitter and "the new york times." "the new york times'" spokeswoman tells abc news their outage was affecting some users but the attack did appear to be malicious. >> worries over syria are taking the toll on wall street. the dow lost 170 points. the nasdaq closing off 70.