The President announced that the US was pulling out of the Iranian Nuke Agreement and I think this is a perfect example of the difference between the political class and the private class.
First of all the President is from the private class so he is making decisions based on performance and results. The Iranians have been violating the agreement from the beginning. This is the worlds largest sponsor of terrorism; why should we trust them. Here is their history. This history is no secret and they have shown no indication of stopping.
While everybody has been concentrating on ISIS, Iran has been pursuing their long term goal of surrounding and annihilating Israel. This is their record and this is why Trump withdrew.
In the political class it's all about feelings. This was about a legacy not about security. Kerry ignored Iran's repeated violations. All they care about is the symbolic legacy. The political class, symbolism over substance.