Advocates say the Social Security Fairness Act rights a decades-old disparity, though it will also put strain on Social Security Trust Funds, which face a looming insolvency crisis.

For the past half-century, union officials representing these groups have been pressuring Congress to eliminate WEP because they wrongly think the law cheats their members out of Social Security benefits they are due. In each of those years, a bill to eliminate WEP has failed to get approved.