Jared Bernstein, a former chief economist to Vice President Joe Biden, is a senior fellow at the Center on Budget and Policy Priorities and author of 'The Reconnection Agenda: Reuniting Growth and Prosperity'.

Republican Sens. Jeff Flake of Arizona and Bob Corker of Tennessee. (Joshua Roberts/Reuters)

In a song about the plight of the leftists in the Spanish Civil War against General Francisco Franco, the great musical satirist Tom Lehrer sang: “Though he may have won all the battles, we had all the good songs.”

That line keeps coming back to me during the tax-cut debate. The opposition to this wasteful, needlessly debt-inducing, regressive monster is, as I’ll show below, serving up clear analysis of the deep shortcomings of the plan. The nonpartisan scoring agencies are doing their work quickly and efficiently, producing data that in a sane debate would have sunk the plan weeks ago.

The media is generally getting it right, regularly reporting such analysis and challenging the falsehoods asserted by the plan’s advocates. These dynamics appear to have turned public opinion solidly against the plan, which in one recent poll had a 25 percent approval rating, as a majority (61 percent) correctly recognized that the plan favors the wealthy.

Yet, a version of the plan has passed the House, and it remains alive in the Senate. True, there are more than enough Republican senators on the fence that the tax plan could go the way of the Republican health plans. If the Democrats stick together, the Republicans can afford to lose only two votes in the Senate. This isn’t over.

But in the spirit of diagnosing a serious malady in the body politic, it is worth examining how the will of wealthy, conservative donors and the perceived need among Republicans to post a win, any win, are thwarting the will of the majority. It’s an especially timely question given that many who will be hurt by the plan are middle- and moderate-income households that helped elect President Trump, who, in a lie echoed by many in his administration, calls the plan a “middle-class miracle.”

Let me quickly review the facts as to why, if there’s a miracle here, it’s that we’re still arguing about trickle-down economics and that supposedly moderate conservative senators still think the cuts have merit.

— Surely, the most remarkable finding is this: According to nonpartisan analysis, by the time it’s fully phased in, the Senate plan increases taxes, on average, on most taxpayers, including all households with incomes under $75,000 (see figure). This is partly because the individual tax cuts for moderate-income folks phase out, while the corporate and estate tax cuts for the wealthy live on.

— The plan will raise the national debt by $1.5 trillion to $2 trillion. And, in regard to the point made above, when Republicans say future Congresses won’t allow planned phaseouts to occur, they’re also saying the deficit impact will be even more negative than current scores show.

— The large growth effects advertised by the administration — large enough, by some of its claims, to more than offset the cost of the plan — have at least two fundamental problems. First, they’re implausibly large, with not an iota of evidence to support them, and second, as I explain here, they imply much larger trade deficits. Note that this latter fact is widely agreed upon, even by advocates of the plan.

— The damage to household incomes shown in the above figure tells only the first part of the story. As I argued at the beginning of this debate, the play among cynical conservatives is to use the deficits they’re creating to insist on spending cuts later (and “later” is almost here). So, low- and moderate-income families get hit twice. They get dinged by the plan itself, and then again by the spending cuts it enforces down the road.

When I listen to some of the Republican fence-sitting senators, including Susan Collins (Maine), Jeff Flake (Ariz.), John McCain (Ariz.), Bob Corker (Tenn.) and Lisa Murkowski (Alaska), I often hear rational, thoughtful voices that would not be willing to provide the marginal vote to support the outcomes noted above. Supporting the plan is simply inconsistent with many things they’ve said and with the visions they’ve espoused.

Of course, the central point of this little essay is that we live in an era in which such inconsistencies are the norm, an era characterized by a constant fuselage of lies from those in power, amplified by social media, where facts are just as unwelcome as a deliberative process that could, at least in theory, deliver real tax reform. These senators, thus, have a unique opportunity to “walk their talk,” to stand up to these forces that are so quickly eroding treasured institutions.

I don’t mean to be melodramatic, but that’s what is at stake here, and any politician who shoves these realities aside to meet the demands of their donors or the exigencies of party politics must question whether that’s what they came here to do. If the answer is “yes,” then I humbly submit that they are serving neither their constituents nor the country.