the court stated, adding, “It upsets the legislative balance to push the outcome farther in either direction. Just as a court should not use section 510 and ERISA’s other fiduciary obligations to curtail the employer’s right to modify a plan, so a court should not use the employer’s power to amend as a reason to curtail section 510.”
Finally, the Seventh Circuit concluded, “Section 510 does not distinguish between vested and unvested benefits. It forbids adverse action ‘for the purpose of interfering with the attainment of any right to which such participant may become entitled under the plan.’ ‘Plan’ includes both pension and welfare plans; the former category includes some vested benefits, the latter does not.”