(MCT) — A public pension overhaul bill rolled out by rank-and-file House lawmakers Wednesday drew fire from unions as backers started the arduous task of building support to pass it.

The financial impact of the plan still must be calculated to ensure it works, though proponents expect savings to be significant enough to fully fund the heavily indebted pensions in 30 years. In addition, House and Senate lawmakers need to iron out differences on whether they think the bill would pass constitutional muster.