And the volley is back in Target's court ...

To recap the day so far: A group associated with investor William Ackman called for two Target directors to resign this morning, citing a rule in the company's governance guidelines. Target fired back a couple of hours later accusing Ackman of trying to fool shareholders.

Backstory: Ackman's hedge fund controls about an 8 percent stake in Target. He's publicly fought with the company over credit-card policies and real-estate investments and will seek to elect himself and four allies to Target's board of directors on Thursday.

The investors' group, Nominees for Shareholder Choice, has fired back this afternoon, this time using the words of Ken Dayton, a member of the company's founding family, to back up its belief that the two board members, who recently left their executive positions at major companies, should resign:

According to this afternoon's press release, Dayton explained the company's policy in a 1984 Harvard Business Review article:

"To keep our board young, vital, and independent - and to ensure a steady flow of fresh blood and new thinking - we have rigid policies of rotation and retirement. We expect directors to submit their resignations at age 65, or after 12 years of service, or whenever a significant change in their positions occurs."

Should we expect another rebuttal from Target today, or will the two sides call a truce until after the holiday weekend?