AUSTIN -- Democrats mostly don't talk about immigration.

It's much easier just to blame Republicans for fouling it up.

So it was a shock Saturday when Democrats not only discussed illegal immigration -- but argued over it.

A spillover crowd triple the expected size showed up for a state convention discussion on "Immigration and the Economy."

A spokesman for a Laredo-based business group argued effectively that as the baby boom generation retires, America will need millions of replacement workers, and that granting work visas or permits might be smarter than building a $50 billion fence.

The discussion was booked for one hour. Speakers were still in line two hours later.

As expected, some Democrats faulted the easy targets: Lou Dobbs, Congress, Farmers Branch and radio entertainers who gripe about people speaking Spanish.

But others in the crowd of 200 also complained about low wages, vanishing jobs, NAFTA and co-workers who can't understand safety warnings in English.

"What I saw today is that Democrats want to discuss immigration, and especially the business side of the debate," said Eddie Aldrete of San Antonio, a banker and spokesman for the Alliance for Security and Trade, an association of South Texas businesses.

"They want to hear something that's fact, not fear. They've heard all about the 'browning of America,' or 'they're stealing our jobs.' They want to know what's true and what's best for the economy."

Ironically, Aldrete's slide show included clips from Demographic Winter, a new documentary promoted by religious conservatives.

In the movie, scientists and demographers warn that the world is running out of children, and that the U.S. will have nobody to work in factories, teach school or care for baby boomers unless we encourage more childbearing.

The movie's points also apply to the immigration debate: What if fewer young workers come to America, and our children wind up footing the entire bill for boomers' Social Security and Medicare? After the video, Aldrete asked rhetorically, "How do we solve this problem? Well -- Congress decided to build a wall."

Earlier, he quoted numbers indicating that 15 million jobs will go unfilled when baby boomers retire, including nearly half our city, county and state government workers.

The business group he represents is nonpartisan, Aldrete said. But recently, a Democratic candidate asked for campaign advice.

"He was trying to argue immigration as a human rights issue, and he was getting his tail kicked," Aldrete told the crowd. "I told him to look at it from a business side. This is not a Democratic or Republican issue. This is a business issue based on sheer numbers."

One Democrat complained that instead of hiring immigrants to work in the fields, Americans should raise their children to play and work more outside.

But he didn't say how many of his children plan careers laying bricks or mowing lawns.

A late arrival was appeals court Judge Linda Yanez, running for the Texas Supreme Court. As a child, she was punished for speaking Spanish in her Rio Hondo school. She was surprised when she could barely squeeze into the room.

"It just shows that Democrats want to talk freely and ask questions about immigration," she said.

Maybe the Democrats have figured out how to argue immigration as good business.