The top Democratic presidential candidates on Wednesday threatened to sit out one of the last scheduled debates of the primary season, saying they would not cross a picket line to attend the CBS event if news writers decide to strike.

The issue quickly became a cause celebre for candidates the day before Thanksgiving after Hillary Clinton released a statement saying she hopes both sides will reach an agreement at CBS, but that she would "honor the picket line if the workers at CBS News decide to strike."

The debate is scheduled for Dec. 10 in Los Angeles.

John Edwards, on a conference call with reporters, said he too would not cross the picket line in the event of a strike. Edwards, who a week earlier walked the Writers Guild picket line in California, also released a statement saying he and his wife Elizabeth were canceling their appearance on "The View" next week in honor of the strike.

"I am a strong believer in collective bargaining, and I hope that in each of these disputes management and the union are able to agree on a just settlement. But until those settlements are reached, I will stand firmly with these workers in their fight for a better life," he said.

Barack Obama's campaign quickly followed suit, as did the campaigns of Bill Richardson, Joe Biden and Chris Dodd, saying they would not attend the debate if there were a strike.

CBS News writers on Monday authorized their union leaders to call a national strike. About 500 of the network's television and radio news writers in New York, Los Angeles and other cities have been working under an expired contract since April 2005.

CBS News called the vote "unfortunate" and said its latest offer was "fair and reasonable."

Democratic National Committee spokeswoman Karen Finney said the committee would monitor the CBS labor situation, and she indicated the party would cancel the debate in the event of a strike.

"The Democratic Party believes the right to organize and collectively bargain is one of our most fundamental rights, and we are proud to stand with the working men and women in the labor movement," Finney said. "Given the Democratic Party's long history of supporting the labor movement in America, if the strike is still going on, we will not cross the picket lines."

The Associated Press contributed to this report.