Why can’t the Saudis invade?

Here’s something I don’t understand. People are mad at the US for not intervening in Syria before the election in November. But I never understand why it always has to be the US that intervenes. Why can’t farmboys from Normandie or Bavaria parachute in and get the job done? Or better yet – farmboys from Jeddah or Medina?
Actually, the Saudi option has many advantages:
• It’s an Arab army.
• They are a top-ten world spender on military hardware, so they have good stuff.
• They are recently battle-hardened after helping squash riots in Bahrain.
• They are right next-door.
• They are rich enough to reimburse Syria for anything they might break.
So how about it, Saudis? You feel like stepping up and helping out?