that was not controversial among Democrats. I remember in 2007, when John and Teresa were on This Week with Stephanopolis, he asked who was best on the environment - and Teresa immediately said something to the effect that none were strong enough. Kerry, corrected that the Democrats were better than the Republicans. In fact, where this was something both Gore and Kerry were committed to, it was not something that any of the 2008 candidates gave the same priority to.
With Iran, though I think it would not have happened without Kerry, I think Obama gets as much credit for backing Kerry at every point on something that really was controversial within the Democratic party. Even early on, it was clear that the powerful AIPAC was going to fight it tooth and nail. He did not back down one iota even when Netanyahu himself came to the Congress - in what ended up being a counterproductive act for the forces wanting to split Democrats from Obama. Obama used his political capitol to prevent them from sinking the agreement. There is no way that a President measuring everything by what political gain is in it for them would have backed this effort at all. I do not think it would have happened under a President Clinton had she won in 2008 - no matter who the SoS was. I have heard Kerry passionately praise Obama for his support and it seems genuine.
In reality, the President in office often gets credit not just for things like these where it was done in the executive branch, but for legislation they sign into law. Consider Nixon gets credit on DU for the EPA and W gets credit in the mainstream media for the increase spending to combat AIDS that occurred when he was President - more than Frist and Kerry, who pushed for legislation much earlier. Not to mention that the Clintons take credit for the Kennedy/Hatch designed SCHIP.