The good news about U.S. President Donald Trump's proposed 2020 budget is that it vividly illustrates the basic causes of large, chronic deficits — a mismatch between the government's commitments and the taxes needed to pay for them. The bad news is that the budget does virtually nothing to close the gap.

"We must protect future generations from Washington's habitual deficit spending," Trump said in his budget message. Actually, he would make matters worse.

Under his budget, the federal government would spend $4.7 trillion in fiscal 2020, a 15 percent increase from the $4.1 trillion in 2018. With tax receipts at $3.6 trillion, the projected deficit is $1.1 trillion. Although the economy is at or near "full employment," the annual deficit remains around $1 trillion until 2023 and then begins to decline, though it's still in deficit by 2029 when the projections stop.