I'm getting the feeling he really did voluntarily step down to save the company. But if he wanted to fight it he might have a good case, as per California Labor Code - Section 1101:

>No employer shall make, adopt, or enforce any rule, regulation, or policy:

>(a) Forbidding or preventing employees from engaging or participating in politics or from becoming candidates for public office.

>(b) Controlling or directing, or tending to control or direct the political activities or affiliations of employees.

>- See more at: http://codes.lp.findlaw.com/cacode/LAB/1/d2/3/5/s1101#sthash...

The other paradox is that this might do more damage to Mozilla than if he stayed, the reaction is pretty split but a lot of people see this as an act of cowardice on Mozilla's part. I'm personally finding it hard to respect how they handled it.