The National Potato Council has been pushing for years to right what it considers a fundamental wrong: the exclusion of white potatoes -- and only white potatoes -- from a list of permissible fresh produce in an important food-assistance program.

As Washington trade association go, the group isn't a powerhouse.  As I've written before, it's "just five people in a downtown Washington office with potato posters on the walls, a few Mr. Potato Heads scattered around and a modest lobbying budget."

But potatoes are grown in many parts of the country, giving the potato crowd support in lots of Hill offices. And the group has recently boosted its spending on lobbying, and on political candidates.

This week, there were signs that all that effort may be paying off. The agriculture appropriations bill for fiscal year 2015 unveiled by the House Appropriations panel would add white potatoes to the list of fresh vegetables that can be bought with monthly vouchers provided under the Special Supplemental Nutrition Program for Women, Infants and Children, known as WIC.

And on Thursday, the Senate Appropriations Committee also voted to include fresh potatoes in WIC. The amendment the panel adopted -- written by Sens. Susan Collins (R-Maine) and Mark Pryor (D-Ark.) -- also requires a government review of all fresh produce, and gives the administration the authority to remove potatoes if the study finds they shouldn't be included.

In the past, some food, health and science advocates have argued that Congress shouldn't meddle in the science used to determine what's included in WIC. The Agriculture Department has said that white potatoes are the most widely used vegetable, and that adding them to the program wouldn't further the goal of expanding the types of fruits and vegetables available to WIC participants.

The folks at the potato council acknowledged that they'd had a good week. "We look forward to the review of the fruit and vegetable components of the WIC food package, which we believe will maintain the valuable role of fresh potatoes in WIC participants’ diets," the group said in a statement.

But it said it's too soon to declare victory. As spokesman Mark Szymanski put it, "We support any and all efforts to get this done and will wait to see what comes out of Conference."