Senate Majority Leader Harry Reid (D-Nev.) on Thursday left open the possibility that Sen. Joe Lieberman’s (Conn.) status as an influential chairman in the Democratic Conference may not be solid for the long term, even as he reiterated the Independent Democrat’s importance on key party priorities.

Reid’s mixed messages on Lieberman come one day after the Connecticut Senator launched public attacks on the Democrats’ newly anointed presidential hopeful, Sen. Barack Obama (Ill.). Lieberman has long backed the presumptive GOP presidential candidate Sen. John McCain (Ariz.), but took that support to a different level in attacking Obama this week.

“I’ve had a conversation with Joe Lieberman of some length — I’m not going to discuss those conversations here,” Reid told reporters, but he was quick to add that “we’ll let the future decide” Lieberman’s long-term role as a key party chairman and member of the Conference.

Reid said he was “not going to threaten anyone here.”

The Majority Leader’s posture Thursday mirrored the fine line he’s walked on the delicate issue of Lieberman’s role in the party for months. Reid has been reluctant to criticize Lieberman — a longtime friend — ever since he switched from the Democratic party to become an Independent Democrat nearly two years ago.

In that vein, Reid made clear that Lieberman still sides with Democrats on issues of importance, pointing to Wednesday’s Senate vote on a budget resolution on which Lieberman sided with the caucus.

“Without Joe Lieberman, the budget might not have passed,” Reid said. “Everyone understands Joe Lieberman made a decision on issues related to the war and has made a decision to support John McCain.”

But, Reid said, “Joe Lieberman is an important vote for the caucus.”