Nearly 46 million people in America lack health insurance, according to the U.S. Census Bureau, and the cost to the country adds up to tens of billions of dollars.

Directly or indirectly, the states pick up much of this tab. Uninsured individuals flood state-subsidized clinics and emergency rooms. States also bear the treatment costs for chronic illness among the uninsured. And a population that is not well cannot function to full capacity, hampering a state’s productivity.

The issue is so pressing that in the last two legislative sessions, more than a dozen states have moved to overhaul coverage for the uninsured. In the absence of federal policy or Washington leadership ready to take on the issue, more and more states are making the uninsured a top priority.

Late last month, Vermont became the third state to approve near-universal health insurance. Crafting the Catamount Health plan required three years of wrangling among the state’s Republican governor, Democratic-majority legislature, top state officials, doctors, insurance providers and private citizens.

Vermont Secretary of Administration Michael Smith said a single imperative propelled this cumbersome process: “We all agreed that if we didn’t start curbing these costs, we were going to be broke.”

The Vermont experience reflects a growing national trend, said healthcare analyst Laura Tobler of the National Conference of State Legislatures: “States are moving ahead with reform because there is no momentum at the national level.”

A lack of federal action also has prompted new state laws encouraging greater use of renewable energy and limiting green-gas emissions. Several states have filled a federal law vacuum on the use of stem cells. And with no movement in Washington, some states have moved to raise their minimum wage.

With health insurance, legislators are responding to clamor from voters who say they cannot afford the kind of regular medical maintenance it takes to stay well – and really cannot afford treatment if they get sick.

State lawmakers know they keep their jobs by creating policy that people want and need, Tobler said.

As large and small employers slash insurance benefits – sometimes eliminating coverage entirely – much of the states’ efforts are directed at the working poor. Health insurance premiums also have climbed so high that some people cannot afford coverage even when they are eligible, Tobler said.