Romney and his personal characteristics (eg deception) are just the avatar of the actual threat -- the republican project to dominate American society from a worldview that only a minority accepts.
Obama has a well developed campaign that can and should win the Presidency as our champion. That is his job.
What is mine? I find a republican - candidate, officeholder, idea, ballot question, my brother-in-law -- that is vulnerable to whatever influence I can bring to bear, and focus MY energy on defeating that republican. When possible, find a partner, work together to magnify OUR effort. Sometimes I/we succeed.
Don't stop when this election is over, that's when the next one starts.
There is not a lot of time left.