The public conversation is shifting to jobs and inequality. Obama’s populism seems to be resonating. Polls show strong support for increasing taxes on the wealthy instead of cutting entitlements in order to close the deficit. Even Republicans are claiming to be defenders of the social safety net.

And Dems on the deficit supercommittee are lurching in exactly the opposite direction.

The Center on Budget and Policy Priorities has just weighed in with a scathing new analysis of the proposal Dems on the supercommittee have offered, which includes deep Medicare cuts in exhange for tax hikes that Republicans aren’t going to agree to, ever. CBPP concludes that the offering represents a substantial shift to the right and away from traditional bedrock Democratic principles:

The new deficit-reduction plan from a majority of Democrats on the congressional Joint Select Committee on Deficit Reduction (the “supercommittee”) marks a dramatic departure from traditional Democratic positions — and actually stands well to the right of plans by the co-chairs of the bipartisan Bowles-Simpson commission and the Senate’s “Gang of Six,” and even further to the right of the plan by the bipartisan Rivlin-Domenici commission. The Democratic plan contains substantially smaller revenue increases than those bipartisan proposals while, for example, containing significantly deeper cuts in Medicare and Medicaid than the Bowles-Simpson plan. The Democratic plan features a substantially higher ratio of spending cuts to revenue increases than any of the bipartisan plans.

The analysis concludes that the Dem proposal would include $200 billion in Medicare beneficiary cuts, which would have a significant impact on people with incomes as low as $12,000 or $15,000. For the longest time, Dems had drawn a line against any benefits cuts, insisting they would only agree to cuts on the provider side.

I’ll leave the policy analysis to those who are better at it. But here’s the political question: Does this risk undermining the momentum Dems have built up with their newly aggressive populism?

After all, we’re now at a point where Republicans are, in rhetorical terms at least, moving towards the Dem position on entitlements , with the RNC sending out a fundraising email making a bleeding heart appeal to concern about the safety net and the poor. With polls suggesting Dems are winning the argument over economic fairness and inequality, does this kind of of proposal risk undermining the sharp contrast between the parties that has been brought into relief by resurgent populism? That’s the case made by many on the left.

The response from some establishment Dems to this question is: No, the public will still appreciate that Republicans are the ones who want to destroy Medicare to preserve tax cuts for the rich, while Dems are the ones who want to save it. Sure, Dems acknowledge, Republicans will seize on Dem-proposed Medicare cuts to muddy these waters. But the public will see through this tactic and understand that Dem cuts are about strengthening Medicare’s finances, while Republicans want to undermine it by transforming it into something no longer recognizable.

The supercommittee may never reach a deal, but some on the left worry that by even offering such a proposal Dems risk undermining their edge in the new environment. Dem leaders tend to dismiss this argument. So I wanted to throw the question out there: Who’s right?