But what if employers just dispense with the formalities and automatically enroll new workers in 401(k)'s?

Starting from October 2012, employers will begin to automatically enrol eligible workers into a qualifying pension scheme and contribute to that pension.

Companies are automatically enrolling workers in 401(k)'s, for example, and increasing their contribution rates over time.

Enrolling new workers before the company knows which ones will fall away and which will stay on would be prohibitively expensive, he said.

Labor Department rules issued last fall make it easier for companies to automatically enroll workers in 401(k) plans.

The bill adopts a play-or-pay system whereby employers provide basic medical insurance or else pay a tax to enroll workers in a public program called AmeriCare.

Companies can now enroll workers automatically, and the Internet has made benefits administration easier for employers.

Unions believe the decision will make it easier to enroll workers.

Like the National Labor Union, it was a federation of different unions and did not directly enroll workers.

Employers would enroll workers in private plans or else pay a tax to enroll them in a public backup plan.