In the absence of a job guarantee, things get trickier. Leaving monetary (and exchange rate) policy aside, the government has to allow the deficit to go where it needs to go in order to accommodate the private sector’s net savings desires. If the private sector wants to spend less and save more, the public sector will need to accommodate that desire by running a bigger deficit or the economy will be pushed away from full employment. Krugman drew up the perfect schematic—based on the sector balance framework adopted by MMT—to explain all of this 10 years ago.
Is there no ability to substitute monetary for fiscal policy? Not much. Krugman sees MMT as saying that fiscal policy can always deliver the “right size” deficit to maintain full employment. He’s challenging that by asserting that you can have any size deficit and still have full employment because the central bank can always establish the “right size” interest rate to get you there. I disagree.
It is true that the Fed can pursue any rate policy it desires. It does not follow, however, that cutting interest rates will work to induce enough spending to maintain full employment. You can’t simply assume borrowers will always have the appetite for more private debt, even if you make it really cheap to borrow. Businesses borrow and invest when they’re swamped with customers (or expect to be). They don’t passively take on more debt simply because the central bank has dangled cheaper credit before them.
The evidence suggests that interest rates don’t matter much at all when it comes to private investment: J.P. Morgan (here and here), the Reserve Bank of Australia (here), the Federal Reserve (here) and the Bank of England (here). It is even possible, as MMT has shown, that cutting rates could further slow the economy because lowering rates cuts government expenditures (interest payments), thereby exacerbating contractionary fiscal policy.
This is in fact what modern monetary theory suggested when the European Central Bank went to negative rates, which MMT sees as a contractionary tax. But MMT recognizes that raising rates could offset contractionary fiscal policy, though in a highly regressive manner as the interest paid by the government tends to go to those with the highest incomes.
Does expansionary fiscal policy reduce interest rates? Yes, unequivocally. You won’t see it in Krugman’s stylized graphic (below), but it does happen in the real world, where the interbank market exists.
Imagine the government is running a trillion-dollar deficit, sending out checks for military weapons, contracting to do massive infrastructure projects, and so on. All of those checks get deposited into financial institutions across the country. And each time a check is deposited, the bank gets a credit to its reserve account at the Fed.
When you pay your taxes, your bank loses reserves, but with a trillion-dollar deficit, there is a huge net infusion of reserves into the banking system. If the central bank takes no action to prevent it from happening, the overnight lending rate—the federal funds rate—will fall to a zero bid.
Why? Because all banks are flush with non-interest-bearing reserves, and everyone is scrambling to lend them to another bank. When everyone’s a seller and no one’s a buyer, the price goes to zero. To prevent this, the central bank steps in.
Before the collapse of Lehman in 2008, the Fed conducted open-market operations (selling bonds to mop up enough reserves to get the interest rate up). This was all coordinated with the Treasury Department on a daily basis, as I explained here.
Today, the Fed simply pays interest on reserves to establish a positive rate. That doesn’t change the fact that deficits, in and of themselves, put downward pressure on the short-term interest rate.