Yes, but not always. He opposed the government option. Quoting the article [0]:
> ... "if the bill remains what it is now, I will not be able to support a cloture motion before final passage." In other words, Lieberman will support a filibuster. "I can't see a way in which I could vote for cloture on any bill that contained a creation of a government-operated-run insurance company," Lieberman said.
> ... "if the bill remains what it is now, I will not be able to support a cloture motion before final passage." In other words, Lieberman will support a filibuster. "I can't see a way in which I could vote for cloture on any bill that contained a creation of a government-operated-run insurance company," Lieberman said.
[0] http://www.slate.com/articles/news_and_politics/prescription...