A top Obama campaign adviser is taking sides in a member-versus-member primary in New Jersey, with senior adviser David Axelrod set to campaign for Rep. Steve Rothman (D-N.J.), according to a national Democratic aide.

Rothman faces Rep. Bill Pascrell in a North Jersey district that was merged by redistricting. Details of Axelrod’s visit weren’t immediately known.

President Obama himself isn’t taking sides in the primary, but Rothman forged ties with his campaign in the 2008 race, when Pascrell endorsed Hillary Clinton in the Democratic primary.

This is yet another race where those 2008 endorsements have become relevant in the 2012 congressional primary season.

Bill Clinton endorsed Pascrell this month, making this race the seventh in which he has supported a Hillary-endorsing candidate against an Obama backer.

While Clinton has been open about his endorsements, Obama is less able to take sides in matchups between incumbents. Instead, his campaign has sent more subtle signals.

Former congressman Patrick Murphy got his own visit from Axelrod in last month’s Pennsylvania attorney general race. And last week, Rep. Howard Berman (D-Calif.), who faces Rep. Brad Sherman, got to ride with the president on his way to a fundraiser with George Clooney. Berman and Murphy both face (or faced) Clinton backers.