US Democratic presidential candidates will take to the debate stage on Saturday night (local time), amid fresh hostilities and accusations Bernie Sanders' campaign stole voter information from Hillary Clinton.
Up until now the Democratic race has been largely devoid of drama, unlike the much more contentious and unpredictable Republican contest.
The accusations are expected to dominate the debate in New Hampshire – the party's third and final debate of the year.
Ms Clinton and Mr Sanders will be joined on stage by former Maryland Governor Martin O'Malley.
The debate is expected to draw low viewership, thanks to the timing on the last weekend before Christmas.
The challenge for Ms Clinton will be to forcefully confront Mr Sanders on the data breach and defend the Democratic National Committee's (DNC) decision to cut off Mr Sanders' access to the party's voter database.
Mr Sanders has pounced on the DNC's actions in recent days, claiming in an email to supporters that the party's establishment had placed "its thumb on the scales in support of Hillary Clinton's campaign".
A worker in the Sanders campaign has since been fired over the breach, and campaign manager Jeff Weaver called the actions "unacceptable".
Mr Sanders' campaign sued the DNC to regain access to the voter records and claimed its actions caused Mr Sanders "injury and financial losses".
The DNC has since restored the Sanders campaign's access to the voter file and is investigating the breach.