Are Democrats really going to go into the 2004 elections opposing a $400 billion expansion of Medicare, a program identified with their party since the time of Harry S. Truman? [IMGCAP(1)]

And are conservative House Republicans really going to block passage of a Medicare prescription drug benefit and deny their president and party leadership both a major domestic accomplishment and a chance to seize the senior vote away from Democrats?

It’s not clear what’s going to happen in either the House or the Senate over the next few days (or weeks, if Congress can’t get its work done promptly), but Democrats seem to have made their decision: They are now positioned staunchly against the largest expansion of Medicare since its founding.

They say that the Medicare bill now before Congress, mainly written by Republicans, is “not good enough” and would actually harm some low-income seniors. They evidently think they can convince seniors that what the GOP is delivering is worse than what they have now — which is no benefit at all.

It strikes me as a massive political gift to the Republicans, who — if conservative House ideologues don’t blow it — will be able to claim to senior voters that they delivered on a major promise and steal an issue that has always benefited Democrats.

At the moment, it appears that Senate Democrats won’t be able to muster the 41 votes needed to filibuster and kill the GOP Medicare bill. If they could, this would once again make Democrats open to the charge of obstructionism.

But the party’s position on the measure itself is fixed. Every party leader in Congress opposes the bill, as does every Democratic presidential candidate except Sen. Joe Lieberman (Conn.), who’s still undecided.

Conceivably, Democrats could get out of their political fix by somehow forcing Republicans to amend the bill to make it more liberal — and then claim credit for having done so.

Some health care lobbyists say this is the aim of Sen. Edward Kennedy (D-Mass.), who fostered a compromise Senate bill in July but now hotly opposes the House-Senate measure.

At the moment, however, no top Democrat is talking about fixes or amendments, but only about opposition. House Minority Leader Nancy Pelosi (Calif.) is going so far as to threaten reprisals against Democrats who vote for the bill.

In the process, Democrats have bitterly split with one of their longest-standing allies, the 35 million-member AARP, which has decided that the bill isn’t perfect but is $400 billion better than nothing.

Rep. Richard Gephardt (Mo.) said in a New Hampshire debate sponsored by the AARP that the group had “fallen into the trap of the pharmaceutical companies and the HMOs.”

And, the newly formed “nonpartisan” Democratic think tank, the Center for American Progress, put out a broadside accusing the AARP of actually being an insurance company and a pharmacy, noting that AARP subsidiaries offer insurance and drugs to members.

Pelosi is encouraging Democratic House Members to quit the AARP, and she and Senate Minority Leader Tom Daschle (S.D.) are assembling a coalition of other seniors’ and health groups to counter the AARP, which has mounted a $7 million ad campaign to promote the Medicare bill.

On its side, AARP National Policy Director John Rother told me he thinks the Democrats’ behavior is “more about politics than policy” and that their aim is to deprive President Bush of a domestic achievement.

Asked particularly about Kennedy, Rother said, “I think this is a tragedy for him. He was such a statesman in July. But now Iraq has deteriorated. The president’s standing in the polls has deteriorated. Blood is in the water as far as the Democrats are concerned. They don’t want prescription drugs to be the thing that saves Bush’s hide.”

One well-informed health care lobbyist said the AARP’s split with the Democrats was by itself “powerful, visible, concrete evidence of the new reality in Washington. Republicans are in charge and are going to stay in charge.”

The AARP’s president, Bill Novelli, told me that backing the GOP bill was “a hard decision,” but that “we are a nonpartisan organization. We are lined up behind seniors. We want the $400 billion to help people with high drug costs.”

Novelli disputed Democratic claims that the bill would undermine traditional Medicare, hurt poor seniors and cost millions of retirees their employer-paid health insurance.

AARP decided to support the measure when House-Senate conferees agreed to a “contained and constrained” test of competition between Medicare and private insurance in 2010. He said that poor seniors would pay no premium — just $1 for a generic prescription and $3 for a brand-name drug.

The bill also contains an $80 billion subsidy to encourage employers to maintain their retiree insurance, he said, plus new benefits such as chronic disease management, preventive care and electronic processing of prescriptions to reduce medical errors.

In the meantime, House GOP leaders are expressing confidence that they can prevent conservatives from blocking the bill. The original House version passed by only one vote, with 19 Republicans defecting and nine Democrats voting in favor. House leaders are emphasizing that the new measure creates tax-deferred health savings accounts for all Americans, a stronger private-sector alternative to traditional Medicare for seniors who want it and other items long sought by conservatives.

According to Democratic pollster Mark Mellman, his party can gain more by allowing the GOP bill to pass — and then attacking it for its flaws — than by blocking it with a filibuster, assuming the votes are there.

“First,” he said, “seniors are going to expect a benefit right away and only get a 10 percent discount until 2006. Then, they’ll get out their calculators and many will see that they don’t get much benefit at all because of premiums ($35 a month), deductibles ($275 a year) and doughnut holes (no coverage between $2,200 and $3,600) in outlays.”

But there is an answer to that and the AARP is emphasizing it in its ad blitz: This bill isn’t perfect, it’s a first step. And, when did Congress ever enact an entitlement program and not make it richer over time? Democrats, it strikes me, have put themselves on the losing end of one of their favorite issues.