The relief of sanctions enabled Iran to fund their other activities in Iraq, Lebanon and Yemen. It also enable the regime to invest in other weapons programs including weapons Iran has been supplying to Russia and those it and its proxies are launching against Israel.
I'm not sure Trump withdrawal from that deal was the best idea but the deal wasn't great either.
The deal did address – quite precisely and successfully – the core issue. It didn't address some other side issues.
"The thing that prevented them from achieving a nuclear weapon didn't also prevent them from funding x y z other far less problematic things that can be far more easily handled through conventional diplomacy and military action"
https://en.wikipedia.org/wiki/Joint_Comprehensive_Plan_of_Ac...
The relief of sanctions enabled Iran to fund their other activities in Iraq, Lebanon and Yemen. It also enable the regime to invest in other weapons programs including weapons Iran has been supplying to Russia and those it and its proxies are launching against Israel.
I'm not sure Trump withdrawal from that deal was the best idea but the deal wasn't great either.