In a pinch Israel would not be asking for US permission to retaliate in kind to an attack from the Saudis or anyone else. Was your reference to "6 days" a coincidence or are you intentionally reminding us of Israel's incredible victory over all of the Arabs in 67? I wouldn't be so sure who would and would not support Israel in an attack if I were you.
Militants in Sinai shell house, killing family of five, say Egyptian officials (AP)
from the article: Gates says Washington to sell smart bombs to Saudi Arabia