It's very unlikely he would have gotten this prize as a U.S. senator not involved in presidential campaign.
I like to see that Nobel Prize as having been awarded to the American voter. Electing a black president in a country with such a racist past is a fantastic milestone.
The second term election of GWB was so surreal by European eyes that it seemed like some collective insanity had gripped large parts of American voters.
In response, when Obama was elected, there were election day parties many places in Europe. Some Americans celebrating always happens, of course, but this time you had Europeans going to parties to celebrate a US president.
The relief was the election of Obama brought was immense, and the Nobel prize is a reflection of just how deep felt it was in certain circles.