I was struck by three things.
First, if he moves to national prominence as a co-frontunner, it will become clear that he is already running against Rudy Giuliani in his hope versus fear pitch.
I'll be a president who ends this war in Iraq and finally brings our troops home who restores our moral standing, who understands that 9/11 is not a way to scare up votes but a challenge that should unite America and the world against the common threats of the 21st century.
But that can also play to the concern among the Democrat base of a Hillary Clinton foreign policy risking being 'Bush-Cheney lite' without having to go too negative.
Second, that Obama's response to the Hillary Clinton argument on different approaches to change is to claim to represent and unify the Obama-Clinton-Edwards strategies, of hoping, working for and fighting for change.
For many months, we've been teased, even derided for talking about hope. But we always knew that hope is not blind optimism. It's not ignoring the enormity of the tasks ahead or the roadblocks that stand in our path.
It's not sitting on the sidelines or shirking from a fight. Hope is that thing inside us that insists, despite all the evidence to the contrary, that something better awaits us if we have the courage to reach for it and to work for it and to fight for it.
Third, that he is making the space to challenge the Clinton campaign if they change strategy and go negative.
That is what we started here in Iowa and that is the message we can now carry to New Hampshire and beyond. The same message we had when we were up and when we were down
Authenticity matters in politics - and Obama has it.