Despite the threat of a historic default looming for Puerto Rico, Senate Democrats are pushing to amend key provisions of a House-passed rescue bill that they say run counter to the party's core principles. Sen. Robert Menendez (D-N.J.), one of the bill's most vocal critics, has prepared amendments that he says he will try to attach even if it means passing the debt-relief package after July 1, when the commonwealth faces a $2 billion debt payment.