Hillary is hoping no one brings this up… 

Mrs. Clinton largely sat on the sidelines when it came to Wal-Mart and unions, according to board members. Since its founding in 1962, Wal-Mart has aggressively fought unionization efforts at its stores and warehouses, employing hard-nosed tactics — like firing union supporters and allegedly spying on employees — that have become the subject of legal complaints against the company.

A special team at Wal-Mart handled those activities, but Mr. Walton was vocal in his opposition to unions. Indeed, he appointed the lawyer who oversaw the company’s union monitoring, Mr. Tate, to the board, where he served with Mrs. Clinton.

During their meetings and private conversations, Mrs. Clinton never voiced objections to Wal-Mart’s stance on unions, according to Mr. Tate and John A. Cooper, another board member.

“She was not an outspoken person on labor, because I think she was smart enough to know that if she favored labor, she was the only one,” Mr. Tate said. “It would only lesson her own position on the board if she took that position.”

Mr. Tate, a prominent management lawyer who helped stop union drives at many major companies, said he worked closely with Mr. Walton to convince workers that a union would be bad for the company, personally telling employees when he visited stores that “the only people who need unions are those who do not work hard.”

http://www.nytimes.com/2007/05/19/us/politics/19cnd-walmart.html?pagewanted=2&_r=1&hp

I never really thought about her time at WALMART.  She was on the board from 1986 to 1992.