Sen. Susan Collins (R-Maine) has been reaching out to Democrats to agree on a compromise that is threatening to divide the president’s party on this core component of its election-year message.

Democrats already disagree among themselves over whether they should continue to stick to the $10.10 amount or try to work with Republicans on a lower figure.

A senior Democratic leadership aide said Reid is a “hardcore” supporter of Obama’s target number, to be achieved over three years, a proposal strongly supported by labor unions, which are powerful in the majority leader’s state.

But several Democratic senators have signaled they are willing to negotiate a lower wage floor that would be easier to get enough Senate votes to pass.