Because Trump canceled the Iran nuclear deal. It's only after he canceled the nuclear deal and reimposed sanctions that they started to enrich uranium again. Everything that has happen since is because of that. The protests against the Iranian government because of the economic crisis. The depreciation of the Iranian rial, soaring inflation, and widespread shortages all due to the sanctions reimposed by Trump. Now the attacks on Iran by the US and Israel, Iran fighting back trying to defend itself other countries being drawn into it thousands dying buildings & infrastructure peoples lives and livings being destroyed. Prices of oil soaring other price rises to follow, more US servicemen possibly going to die or be badly injured, The US spending billions it doesn't have, the whole world suffering and having to deal with inflation or possibly stagflation and more unemployment. The possibility of it even spreading beyond the Middle East sparking a new world war. It's all down to Trump the snake oil salesman who has managed to con the US electorate, He's a con man it's the only thing he is good at.