By Michael Barone - March 28, 2011

The Census Bureau last week released county and city populations for the last of the 50 states from the 2010 Census last week, ahead of schedule. Behind the columns of numbers are many vivid stories of how our nation has been changing -- and some lessons for public policy, as well.

Geographically, our population is moving to the south and west, to the point that the center of the nation's population has moved to Texas County, Missouri.

That sounds like the familiar story of people moving from the Snow Belt to the Sun Belt, but that's not exactly what's happening. Instead, the fastest growth rates in the 2000-10 decade have been in Texas, the Rocky Mountain states and the South Atlantic states.

We're familiar with the phenomenon of people moving to the West Coast. But the three Pacific Coast states -- California, Oregon and Washington -- grew by 11 percent in the last decade, just 1 percent above the national average, while the South Atlantic states from Virginia through the Carolinas and Georgia to Florida grew by 17 percent.

In 2000, the South Atlantic states had 121,000 more people than the Pacific Coast states. In 2010 they had 2.8 million more.

What's been happening is that people from the Northeast and the Midwest have been flocking to the South Atlantic states, not to retirement communities but to Tampa and Jacksonville, Atlanta and Charlotte and Raleigh, which are among the nation's fastest-growing metro areas. The South Atlantic has been attracting smaller numbers of immigrants, as well.

Coastal California, in contrast, has had a vast inflow of immigrants and a similarly vast outflow of Americans. High housing costs, exacerbated by no-growth policies and environmental restrictions, have made modest homes unaffordable to middle class families who don't want to live in Spanish-speaking neighborhoods or commute 50 miles to work.

California for the first time in its history grew only microscopically faster than the nation as a whole (10 percent to 9.7 percent). Metro Los Angeles and San Francisco increasingly resemble Mexico City and Sao Paulo, with a large affluent upper class, a vast proletariat and a huge income gap in between.

Public policy plays an important role here -- one that's especially relevant as state governments seek to cut spending and reduce the power of the public employee unions that seek to raise spending and prevent accountability.

The lesson is that high taxes and strong public employee unions tend to stifle growth and produce a two-tier society like coastal California's.

The eight states with no state income tax grew 18 percent in the last decade. The other states (including the District of Columbia) grew just 8 percent.

The 22 states with right-to-work laws grew 15 percent in the last decade. The other states grew just 6 percent.

The 16 states where collective bargaining with public employees is not required grew 15 percent in the last decade. The other states grew 7 percent.

Now some people say that low population growth is desirable. The argument goes that it reduces environmental damage and prevents the visual blight of sprawl.

But states and nations with slow growth end up with aging populations and not enough people of working age to generate an economy capable of supporting them in the style to which they've grown accustomed.

Slow growth is nice if you've got a good-sized trust fund and some nice acreage in a place like Aspen. But it reduces opportunity for those who don't start off with such advantages to move upward on the economic ladder.

The most rapid growth in 2000-10, 21 percent, was in the Rocky Mountain states and in Texas. The Rocky Mountain states tend to have low taxes, weak unions and light regulation. Texas has no state income tax, no public employee union bargaining and light regulation.

Texas' economy has diversified far beyond petroleum, with booming high-tech centers, major corporate headquarters and thriving small businesses. It has attracted hundreds of thousands of Americans and immigrants, high-skill as well as low-skill. Its wide open spaces made for low housing costs, which protected it against the housing bubble and bust that has slowed growth in Phoenix and Las Vegas.

The states, said Justice Brandeis, are laboratories of reform. The 2010 Census tells us whose experiment worked best. It's the state with the same name as the county that's the center of the nation's population: Texas.