The increase in the deficit in the face of the weakening economy is, in fact, one of the reasons that focusing on the "cash-flow deficit" can be so misleading. It is one thing to say that we are running a deficit of, say, 12% of national income during boom times, but it is quite another to say we are running a deficit of that magnitude during a recession. During a recession, we should expect that the deficit will be temporarily high, for two reasons:
First, when the economy is weak, we collect fewer tax dollars (because so many people have lost their jobs or have seen their incomes fall), and we also have to spend more money on benefits to prevent people from suffering catastrophic and irreversible harm as they try to find new jobs.
The Best and Worst of Spending
Second, the deficit is also higher during a downturn than it would normally be because of the government's attempts to stimulate the economy.