Lieberman briefly joked about how the Republicans might coax him into joining the GOP, a switch that could keep the closely divided Senate under Republican control.
"There is a little playfulness in me that wants me to make a joke about that, but it's too serious. The answer is no," he said. "When I give my word I stick with it, and I am definitely going to organize with the Senate Democrats."
He said he delivered that message Wednesday in a phone conversation with the Senate Democratic leader, Harry Reid of Nevada. He did not take Reid's call on election night.