For a while this spring, it appeared as if the potato had prevailed.

It looked as if members of Congress from potato-producing states — including Maine Sen. Susan Collins — had managed to force the spud into the “food package” of the federal WIC program, which issues vouchers each month that allow low-income pregnant women and mothers with infants and young children to buy a narrow range of specific, nutrient-rich foods.

Now, however, the agriculture appropriations bills with the potato provisions are caught in the same quagmire that has halted countless other bills in Washington, D.C. The likelihood that the potato provision won’t pass — at least this year — could be good news for the Maine families who rely on WIC.

Next year, the WIC food package is up for review by a panel of scientists under a process laid out in federal law. That process deserves a chance to work without congressional and lobbyist interference.

More than half the nation’s infants participate in WIC, short for the Special Supplemental Nutrition Program for Women, Infants and Children. In Maine, about 5,700 infants benefited from the program each month in 2012, along with more than 14,000 young children and nearly 5,500 pregnant, postpartum and breastfeeding mothers, according to the National WIC Association. Each participant received, on average, a $55.23 monthly benefit. (The average monthly food stamp benefit is $133.)

Unlike food stamps, WIC is designed to fill in the nutritional gaps that are common in the diets of low-income women and children. To that end, there’s an emphasis on fresh fruits and vegetables, whole grains and non-processed foods without added sodium and sugar.

That formulation has earned the WIC program high marks: Researchers have found participating mothers are more likely to have healthy deliveries — which cost the health care system less than births with complications — and participating infants are less likely to spend time in the hospital. Plus, experts give the WIC package some credit for the 43-percent drop in obesity among 2- to 5-year-olds that has taken place over the last decade.

But there’s no allowance for the fresh, white potato as part of that formulation — to the chagrin of potato growers and their champions. In fact, the white potato — but not the yam or sweet potato — is the only fresh vegetable that WIC specifically excludes.

That’s the result of a major nutritional overhaul WIC received in 2009 — the first since the program’s 1972 start. The U.S. Department of Agriculture made the revisions largely on the advice of an Institute of Medicine expert panel that recommended the overhaul in 2005, citing modern-day challenges of staying healthy — such as sedentary lifestyles — that weren’t as prevalent in 1972.

Potatoes are a critical part of Maine’s agricultural economy, and the white potato has redeeming nutritional value. But WIC is designed to fill in dietary gaps by encouraging low-income Americans to seek out foods they wouldn’t normally. And “most Americans do not need encouragement to consume the maximum recommendation of one serving of potatoes per day,” the Institute of Medicine panel wrote in a summary of its recommendations for WIC.

Recent data from the U.S. Department of Agriculture bear this out. The potato, in all its prepared forms, is the most common vegetable in American diets — by far. In 2012, the average American consumed 52.3 pounds of spuds, compared with 31.1 pounds of tomatoes, the next most common vegetable (well, technically a fruit).

In 2010, President Obama signed the Healthy, Hunger-Free Kids Act into law. For the first time in WIC’s history, it requires the Institute of Medicine to convene an expert panel every 10 years to examine the WIC food package and recommend revisions based on consumption patterns, recent nutrition science and available foods.

It comes down to this: Do Americans trust scientists or a heavily lobbied Congress to determine which foods deserve inclusion in WIC? We think it’s best to wait a year — the first review takes place in 2015 — to see what the experts determine based on all the facts.