I think overwhelming force is better. The US and its allies showed that that worked in Iraq twice. Word War I was the ultimate example of proportionate force. Neither side was able to overwhelm the other over a period of over four years. The roughly balanced strength of the opposing forces led to incredible amounts of carnage.
IMO, it's Israel's "shock and awe" time and Iran should get the first taste and the second taste goes to Syria. Any hidden WMD's in Syria that come out of their tunnels, caves, or sand pits and it will be our turn as an ally of Israel to use our Navy and Air Force to take care of business.