The federal budget is shrinking — but not because Washington has had an infusion of responsible policymaking.

The Wall Street Journal‘s Stephen Moore highlights the “biggest underreported story out of Washington this year”:

Consider the numbers: According to the Congressional Budget Office, annual outlays peaked at $3.598 trillion in fiscal 2011. After President Obama’s first two years in office, many in Washington expected that number to hit $4 trillion by 2014. Instead, spending fell to $3.537 trillion in fiscal 2012, and is on pace to fall below $3.45 trillion by the end of this fiscal year (Sept. 30). The $150 billion budget decline of 4% is the first time federal expenditures have fallen for two consecutive years since the end of the Korean War.

This reversal from the spending binge in 2009 and 2010 began with the debt-ceiling agreement between Mr. Obama and House Speaker John Boehner in 2011. The agreement set $2 trillion in tight caps on spending over a decade and created this year’s budget sequester, which will save more than $50 billion in fiscal 2013.

As long as Republicans don’t foolishly undo this amazing progress by agreeing to Mr. Obama’s demands for a “balanced approach” to the 2014 budget in exchange for calling off the sequester, additional expenditure cuts will continue automatically. Those cuts are built into the current budget law.