ABC News -- ABC News Jonathan Karl reports: Has Joe Lieberman been bluffing? An article in this morning's The Hill newspaper says Lieberman has "reached a private understanding" with Harry Reid that he won't block a final vote on a health care bill. If true, that would contradict Lieberman's public statements last week, including his interview with ABC News "Subway Series" where he said he would join a Republican filibuster to kill the bill if it included a public option. Lieberman's office, however, says the Hill story is bunk, or, in spokesman Marshall Wittman's words "absolutely not true." Lieberman, Wittman says, will vote to block a final vote on any bill with a pubic option and has no "private understanding" with Reid to the contrary. Witmann...