We can only do the best we can do. Obama had 8 years to clean up this mess. To his credit...I'm sure he did the best he could do too. Either way... don't throw Trump under the bus.... he inherited this sh*t. There is no easy solution or it would have been fixed long before 45.
Iran signed on to a deal that was enforceable, they were open to diplomacy which would have balanced out the Saudi power in the region - Trump has set back that plan for years if not decades with his 'kill everything Obama did' plan.