Recently, a new Arizona law permitted the state to raise money from private and public sources to build a border fence. Republican state senator Steve Smith sponsored the bill, which he hopes will raise the $50 million needed to add new fences and bolster existing ones at www.BuildTheBorderFence.com.

This is a first. No other state has attempted to build a fence using donated money. This effort came after the federal government stopped building the fence, citing cost overruns and technological challenges, especially in their "virtual fence" attempt.  In addition, environmental regulations blocked them from building in certain areas. It is unclear whether or not such donations are tax deductible.

Arizona has about 72 miles of border with no fence on it. This is generally in rugged areas where fences are difficult to build. There are 123 miles of pedestrian fences between 12-25 feet high and an additional 183 miles of barriers that can keep out vehicles but not people.

The problem is obvious. As former Arizona governor Napolitano once said, "You show me a 50-foot wall and I'll show you a 51-foot ladder at the border. That's the way the border works."  Like water flowing downhill, those wanting to cross the border will do so at the point of least resistance. A big fence only stops people in that particular area and not ten miles away where there is no fence.

Environmental groups generally oppose the fences because they block wildlife migration and can cause floods when debris gets trapped in them. The Sky Island Alliance, an environmental group based in Tucson, cites a poll saying that Americans favor strengthening Ports of Entry as the best way to prevent illegal activities, rather than building new fences. I must confess, I don't quite understand the reasoning here. If I'm bringing ten pounds of heroin in a backpack or six illegal immigrants across the border I'm probably not going to cross over at a Port of Entry. Sure, Ports of Entry should be efficient and vigilant, but that's generally not where the action is. In other poll results, Sky Island Alliance found that 64% did not want Congress or Homeland Security to be able to waive environmental restrictions and other laws in order to build a fence.

Another problem is where to build it. It could be sited on a sixty foot strip of land by the border owned by the federal government, but permission to build would be needed. Other parts would be on private land or Indian reservations, further complicating matters.

Let's assume that donations allow the new fence improvements to be built (and this is a big assumption indeed). Would it be able to stop illegal immigration and smuggling?  Fences can be gotten around by going around, under, over, or through them. And then there's the time-honored method of paying someone to look the other way for a few minutes.

The increased security at the border has appeared to slow drug and human smuggling but hasn't stopped it, nor can it. Other solutions need to be found.