I think I heard somewhere that there was a vote in the senate where Barack Obama was the only dissenting vote.
I believe it was a vote to validate a war action.
This would be when Obama was a senator.
Does anyone know of such a senate vote?
I believe this was referring to a vote when he was a State Senator.
The bill was "Born Alive Infant Protection Act", which was a bill directing that live infants resulting from botched abortions are to be provided medical care (including comfort care to non-viable ones).
However, this was a complicated issue (in short, you can't say "Obama was the only dissenting vote"):
Obamas votes and opposition speech transcripts can be found here (pretty partisan site but the links are to State Senate PDFs).