Turkey is also an Islamic country. Iran + Turkey + Iraq = problems. Not that that would happen, but you seem to think we could somehow launch an amphibious invasion (which it would be if the entire Islamic world was allied against us) that would succeed against all that. Not likely.
Not an amphibious invasion. The forces already IN the Gulf were capable of defeating "many Middle East nations". I do not count Turkey as a middle eastern state; rather it is part of Europe (or perhaps if the European part is ignored, part of Southwest Asia, along with Pakistan, the 'Stans & Iran; although I did take Iran as part of the "Middle East").
If we are going to make it ALL of Islam, from Central Asia to the Atlantic clearly the U.S. forces would be swamped. But against the forces that could be brough to bear against the troops already in Kuwait & the Gulf States prior to the 2003 invasion, with the carriers in the Red Sea, Arabian Sea, and Med as back up, with the U.S. forces being able to fight a defensive battle (inside the range of friendly SAM coverage from the Gulf Squadron); against forces speaking different languages, with different combat doctrine and no unified chain of command, and with a preponderance of second rate equipment; that are crossing open desert in full view of Satellites and subject to non-stop air attack, yes, I do like the American chances.