Caretaker Prime Minister Ehud Barak said on Tuesday he will not serve in Ariel Sharon's Cabinet, throwing into disarray plans for a unity government that might renew peace talks with the Palestinians. Mr. Barak had said in recent days he would serve as defence minister under Sharon, drawing a whirlwind of criticism from Labour Party colleagues who charged he had sold out and was trying to hang on to power. They were also angered by his frequent shifts. Right after the election he said that he would resign from politics. But a few days later he decided to join with Sharon, The Associated Press reports. If Barak's latest change of mind means a government without Labour, Sharon will likely be forced into a narrow coalition dependent on right-wing parties - hawks and religious nationalists that oppose any territorial concessions to the Palestinians.