The Arab Gulf states are expressing concern to the United States about its handling of the Iranian nuclear power issue. They have told the U.S. that they will support continued diplomatic initiatives to resolve the crisis, and even economic sanctions. But they are unwilling to support military action, unless it is strongly endorsed by the U.N. Security Council.
The leaders of the Gulf states fear that excessive pressure on Iran, or precipitous military action, may result in serious domestic problems on the Arab side of the Gulf. The ruling classes of most of these states are Sunni. In Oman the Ibadi sect is dominant. But there are often substantial Shia populations in these states. Kuwait is 25-percent Shia; Bahrain, 75-percent; Qatar, 10-percent; the UAE, and Oman, 5-percent (all figures are essentially "official" estimates). While some of the Gulf Shia look to domestic religious leaders, or even to Iraq's highly revered Gand Ayatollah Sistani, most of them are followers of the late Iranian hard line religious leader Kohmeini. The Sunni rulers on the west shore of the Persian Gulf have been trying to appease their Shia minorities, and have been having some success. In addition to passing out more jobs and other goodies to the Shia, everyone is reminded that the Iranians are not Arabs, and have, for thousands of years, been a threat to the Arabs in the region (who, in terms of sheer numbers, do not outnumber the Iranians by a whole lot.)
But if the Americans, and other outsiders, attack Iran, then the Iranians will have some success in calling for "Shia unity." This would manifest itself most dramatically as terrorist attacks. The Sunni Arabs dominate the military and police in all the countries with Shia minorities, but that won't be enough to stop some of the terror operations in defense of Iran.