Should pro-immigration forces favor a fence?

I am beginning to wonder:

Legislation passed by Congress mandating the fencing of 700 miles of
the U.S. border with Mexico has sparked opposition from an array of
land managers, businesspeople, law enforcement officials,
environmentalists and U.S. Border Patrol agents as a one-size-fits-all
policy response to the nettlesome task of securing the nation’s borders.

Critics
said the fence does not take into account the extraordinarily varied
geography of the 2,000-mile-long border, which cuts through Mexican and
U.S. cities separated by a sidewalk, vast scrubland and deserts,
rivers, irrigation canals and miles of mountainous terrain.  They also
say it seems to ignore advances in border security that don’t involve
construction of a 15-foot-high double fence and to play down what are
expected to be significant costs to maintain the new barrier.

And, they say, the estimated $2 billion price tag and the mandate that
it be completed by 2008 overlook 10 years of legal and logistical
difficulties the federal government has faced to finish a comparatively
tiny fence of 14 miles dividing San Diego and Tijuana.

"This is the feel-good approach to immigration control," said Wayne
Cornelius, an expert on immigration issues at the University of
California at San Diego.

Construction of a fence, of course, would defuse many other pressures.  Here is the full story.