Connecticut Senator Joe Lieberman may be the target of intense partisan ire among his Democratic colleagues and the liberal blogosphere, after a Sunday talk show appearance in which he expressed opposition to another component of the Democrats’ healthcare bill, an expansion of Medicare, but a senior aide to the senator tells Fox that Senate Majority Leader Harry Reid, D-NV, knew of the concerns as early as Thursday.

The situation is this, according to the Lieberman aide: the senator’s staff told negotiators last week, when the Medicare buy-in was developed, that he had problems with it.

Last Thursday, Lieberman made his concerns known in a letter to Reid, and Friday, according to the aide, the senator reiterated the concerns orally to the leader during the course of the day.

“It should not come as any surprise to the leadership what the senator’s concerns were. Any contrary suggestions by Democrats under the cloak of anonymity are false and self-serving,” the aide said.

Lieberman sees “much good” in the base bill, including insurance market reforms, the aide said, adding, “He would like to be able to vote for the bill; however, he cannot accept a bill that has government-run healthcare or an expansion of Medicare.”

Lieberman, the aide said, sees the expansion as “unnecessary” and “redundant” in that the base bill that Reid introduced “already addresses the issues of access (with federal subsidies) and cost control.”

Clearly inundated by calls into his office and a general backlash against his boss, the aide said emphatically, “I want to emphasize, he would like to vote for a bill. He’s not opposed to healthcare reform.”

After his Sunday show appearance, Lieberman met privately in Reid’s office with White House Chief of Staff Rahm Emanuel, a fixture these days as healthcare reform gets hammered out, along with other key White House aides that deal with healthcare. This was not a scheduled meeting, and Lieberman’s position and the situation with healthcare reform were the topics of conversation, according to the aide.

The White House is urging Reid to drop a proposed Medicare expansion, which would enable Americans as young as 55 years old, to buy into the program for seniors, this according to congressional staffers. Reid aides say the leader is waiting for an analysis of the proposal, due as early as Tuesday, before making any final decisions.

Senate Democrats are meeting tonight, and Lieberman, a self-styled Independent Democrat, intends to attend, according to the staffer. The focus of the meeting is likely to focus on the very concerns that have brought trouble his way.

Then Senate Democrats are to attend a Tuesday afternoon meeting at the White House in a critical week on healthcare reform, as the Caucus attempts to make good on a pledge to get healthcare reform done by Christmas.