(Decanter) - A wine trade dispute with the potential to set an important precedent on inter-state sales has been heard by US Supreme Court judges this week.

A hearing before Supreme Court justices on 16 January has been billed as potentially the most important case since the Granholm v Heald decision in 2005, which helped paved the way for wineries to sell directly to consumers beyond their own state.

At issue in the current case, Tennessee Wine & Spirits Retailers Association v. Zackary Blair, is the desire of Total Wine, plus a separate couple, to set up wine shops in Tennessee.

State rules say that prospective retailers can only apply for an initial licence after two years of residency. This must be renewed after one year; and the renewal requires a decade of prior residency.

Key to the case is the extent to which states can justify discrimination against out-of-state wine retailers.

This is why several observers believe the Supreme Court ruling, expected in spring this year, may have far-reaching consequences for inter-state wine sales.