Economists generally think that these policies will have a lower “multiplier” than these policies would have if they took place during a recession, when there is more spare capacity in the economy. But that doesn’t mean the multiplier becomes zero.

“Some people assume that because this was a bad process and the tax bill is really regressive that it won’t have a short-term growth impact, but I think that’s wrong,” said Adam Posen, president of the Peterson Institute for International Economics. “We shouldn’t confuse whatever distaste one has for the composition of the package for totally overwhelming the multiplier effects.”

Put a different way, it would be very hard for the government to pump an extra half-trillion dollars into the economy in a single year without getting some extra economic activity out of it.

Another potential near-term positive for the global financial system could be the effect of billions of dollars in bonds issued by the Treasury. For years the world has experienced what some analysts call a “safe asset shortage,” too few government bonds and other investments viewed as reliable relative to demand.

This has arguably been a factor in depressed interest rates and sluggish growth across much of the advanced world. More Treasury bonds floating around might reduce those pressures.

The Medium Term: Depends on Economic Slack, and the Fed

Over the next two or three years, things get more murky. What happens will depend on how the economy responds to the additional fiscal stimulus, and how the Fed responds to that.

The big question is whether the economy has the room to keep growing without higher inflation emerging. The unemployment rate is already low at 4.1 percent, so there aren’t exactly hordes of jobless people available to be put back to work. That means there is a chance that all this extra money flooding into the economy doesn’t go toward more economic output but just bids up wages and ultimately consumer prices.