Iran and it's proxies has been seeding places with a Persian/Lebanese diaspora with agents, Hezbollah has a presence in Latin America and the goal is to cause havoc and facilitate the flow of drugs into the US. (Also to generate cash)
There are some 80 million+ Iranians that want the regime gone. After the massacres in January and now the bombings, the only way the regime can survive is to crack down even harder. However the more they crack down, the less economic activity there is. If this summer is dry, then there will be no water in Tehran. Without economic activity, the funds to pay the regime supporters begin to dry up. While a portion are diehard religious types that will fight to the end, many will simply fade away.
From now on the US and Israel can strike anywhere at any time. So the Regime can't concentrate it's forces. If the rebels can take a city, then the US/IDF can provide air cover and critical supplies.