The contours of a developing “Republicans for Biden” movement are indeed fluid, with longtime operatives and former party loyalists mixed on what a final product would look like and when it might come into fruition. The movement behind-the-scenes is in contrast to the very public effort to unite the left, but matches Biden’s own professed fondness for working with Republicans.

When presented with Biden’s comments, GOP sources interviewed referenced two main possibilities: an external group that would work on his behalf as a political action committee—similar to other Democratic-led outside groups—that could theoretically clear a pathway for others to join; or an internal operation within Biden’s campaign, with one or more recognizable Republican figures joining as the public face.

A second source well-placed in Republican circles—who has had conversations with senior Biden advisers in recent weeks—said that any mounting effort would most likely come from within the campaign’s vast network.

“My impression is the official one will be part of the campaign,” the Republican source said, referencing the apparent “Republicans for Biden” group Biden mentioned himself.