I don’t know yet. But news reports this morning certainly raise questions.

Let’s lay out the basics here. Other things equal, public investment is a much better way to provide economic stimulus than tax cuts, for two reasons. First, if the government spends money, that money is spent, helping support demand, whereas tax cuts may be largely saved. So public investment offers more bang for the buck. Second, public investment leaves something of value behind when the stimulus is over.

That said, there’s a problem with a public-investment-only stimulus plan, namely timing. We need stimulus fast, and there’s a limited supply of “shovel-ready” projects that can be started soon enough to deliver an economic boost any time soon. You can bulk up stimulus through other forms of spending, mainly aid to Americans in distress — unemployment benefits, food stamps, etc.. And you can also provide aid to state and local governments so that they don’t have to cut spending — avoiding anti-stimulus is a fast way to achieve net stimulus. But everything I’ve heard says that even with all these things it’s hard to come up with enough spending to provide all the aid the economy needs in 2009.

What this says is that there’s a reasonable economic case for including a significant amount of tax cuts in the package, mainly in year one.

But the numbers being reported — 40 percent of the whole, two-year plan — sound high. And all the news reports say that the high tax-cut share is intended to assuage Republicans; what this presumably means is that this was the message the off-the-record Obamanauts were told to convey.

And that’s bad news.

Look, Republicans are not going to come on board. Make 40% of the package tax cuts, they’ll demand 100%. Then they’ll start the thing about how you can’t cut taxes on people who don’t pay taxes (with only income taxes counting, of course) and demand that the plan focus on the affluent. Then they’ll demand cuts in corporate taxes. And Mitch McConnell is already saying that state and local governments should get loans, not aid — which would undermine that part of the plan, too.

OK, maybe this is just a head fake from the Obama people — they think they can win the PR battle by making bipartisan noises, then accusing the GOP of being obstructionist. But I’m really worried that they’re sending off signals of weakness right from the beginning, and that they’re just going to embolden the opposition.

Like Barney Frank, I’m feeling a bit of post-partisan depression.

Updates: A few more details are emerging: $140 billion for Obama’s tax break for workers, which gives most workers $500. But it sounds as if the rest is mainly, perhaps almost entirely, tax cuts for business. Not very New Dealish.

Meanwhile, Mitch McConnell, perhaps sensing weakness, is already moving the goalposts.