A Biden family member has threatened legal action over claims of ongoing drug use in the family, a fight that could turn bad for whichever side is bluffing.

• The threatened lawsuit has hung over the dispute for two years without being filed.
• The person making the claims says she welcomes a suit because discovery would force the evidence into the open.
• She insists she was in a position to know first-hand and has documents to back it up.
• The allegation goes beyond Hunter Biden's long-reported crack use to other family members with substance problems.

Outlook: Unless the Bidens actually file, the threat looks like pressure rather than a real legal case, and the claims will keep circulating unchallenged.