The Guardian, now there's an objective paper.
Anyways...
1-What is this conflict about?
Security:
I think the Iranian leaders think if they can equip their country with nuclear weapons, they'll have much more leverage in the world. Things are much different when you can place internal terrorist cells into countries AND you can ensure MAD.
The US might be the strongest nation in the world right now, but it doesn't matter when your enemy can obliterate your country in a heartbeat. Iran is no stranger with terrorist tactics, and those could prove fatal with nuclear weapons. Even without nuclear, Iran could damage the US or her interest indirectly with factions, with little repercussions because of a MAD policy.
2-What leverage does each side have?
The US has the best military and economy to fuel it. Precision and covert capabilities.
Iran has geographical size and population, it would create a very dense situation occupying wise. Incredibly hard, if not impossible (at the moment) for the US to have any real hold on.
3-Where is the conflict heading?
High intensity political
Iranian victory, they will equip themselves with nuclear weapons in the end. There is no stopping them. Any political "victory" the US or allies could receive is fake. The US and Israel can't use their militaries, and Europe is too cowardly.