Trade war: Over the past few decades, businesses around the world invested vast sums based on the belief that old-fashioned protectionism was a thing of the past. But Donald Trump hasn’t just imposed high tariffs, he’s demonstrated a willingness to violate the spirit, if not the letter, of existing trade agreements. You don’t have to be a doctrinaire free-trader to believe that this must have a depressing economic effect.

For now, corporate leaders reportedly believe that things won’t get out of hand, that the U.S. and China in particular will reach a deal. But this sentiment could turn suddenly if and when business realizes that the hard-liners still seem to be calling the shots.

The shutdown: It’s not just the federal workers not getting paid. It’s also the contractors, who will never get reimbursed for their losses, the food stamp recipients who will be cut off if the stalemate goes on, and more. Conventional estimates of the cost of the shutdown are almost surely too low, because they don’t take account of the disruption a nonfunctioning government will impose on every aspect of life.

As in the case of a trade war, business leaders reportedly believe that the shutdown will soon be resolved. But what will happen to investment and hiring if and when corporate America concludes that Trump has boxed himself in, and that this could go on for many months?

So there are multiple things going wrong, all of which threaten the economy. How bad will it be?

The good news is that even taking all these negatives together, they don’t come close to the body blow the world economy took from the 2008 financial crisis. The bad news is that it’s not clear what policymakers can or will do to respond when things go wrong.

Monetary policy ­— that is, interest rate cuts by the Federal Reserve and its counterparts abroad — is normally the first line of defense against recession. But the Fed has very limited room to cut, because interest rates are already low, and in Europe, where rates are negative, there’s no room at all.

Fiscal policy — temporary hikes in government spending and aid to vulnerable workers — is the usual backup to monetary easing. But would a president who’s holding federal workers hostage in pursuit of a pointless wall be willing to enact a sensible stimulus? And in Europe, any proposal for fiscal action would probably encounter the usual German nein.