Just call Vermont the mouse that roared. The state’s mandatory GMO food-labeling law, designed to serve its tiny population of 625,000, probably just changed eating for 320 million Americans.

Thursday, the U.S. Department of Agriculture confirmed that it is, after years of debate, considering an official voluntary “GMO-Free” label for food. To some, the national suggestion of a voluntary label is squishy and without teeth, when compared with Vermont’s mandatory law for labeling anything containing GMOs (which is roughly 80 percent of our food supply). That’s an important discussion.

But equally important is the question why, after years of debate and activists demanding government labeling, would the government act now? According to a May 1 letter from USDA head Tom Vilsak obtained