Tauscher endorsed DeSaulnier in the special election race to succeed her well before she resigned her seat to become undersecretary of State for arms control and international security.

While the endorsement does not break any laws or State department policies, the agency has asked that DeSaulnier stop using Tauscher’s name to avoid the appearance of ethical impropriety, according to a report late last week in the Contra Costa Times.

Many of DeSaulnier’s campaign materials have already been printed, and it doesn’t appear that DeSaulnier has any legal obligation to stop touting Tauscher’s endorsement.

DeSaulnier last month became the first candidate in the race to air a TV ad, which focused on his commitment to health care reform.

In the crowded Sept. 1 all-party primary, DeSaulnier is one of three Democratic frontrunners, along with Lt. Gov. John Garamendi and state Assemblywoman Joan Buchanan. If no one tops 50 percent of the vote, as expected, the top vote-getters from each party advance to a special election two months later.