Last month the U.S. Senate voted to shelve further consideration of a contentious immigration proposal. Various interpretations are offered for the defeat, including a president who has lost much of his political clout and a fractious GOP that refuses to follow the lead of the Bush administration anymore.

The story of why immigration reform failed this year is not simply about the waning power of a lame duck president or in-fighting in the GOP. Senator Claire McCaskill’s no vote offers one clue to the challenge that lies ahead for reform advocates such as the Catholic Church.

Both of Missouri’s U.S. Senators – Kit Bond and Claire McCaskill – voted to put aside the immigration bill. Reform advocates in Washington D.C., including the Catholic Church’s Justice for Immigrants Campaign, had hoped that a freshman Democrat like Sen. McCaskill would support her party leaders. But Senator McCaskill joined with two other incoming freshman Democrats – Jon Tester of Montana and Jim Webb of Virginia – to block consideration of the immigration bill. Why?

All three senators won their 2006 elections by very narrow margins. Senator McCaskill told the New York Times that she ran against immigration reform pending in Congress and she likes to keep her word. In the same Times article, Senator Jeff Sessions of (R-Alabama) told the paper, “Some of the new members looked their voters in the eye and said they were not for amnesty and were for stricter enforcement.”

Popular opinion may not have kept pace with the changes the Senate made to the immigration bill during this year’s debate, such as tying earned legalization to stronger border enforcement. In addition, the immigration debate focused too little on what forces are causing immigration, including the stark reality of Mexican poverty.

For example, a study by the World Bank found that almost 28 percent of rural Mexicans live on less than one dollar a day. And according to some observers, implementation of the North American Free Trade Agreement (NAFTA) in 1994 has exacerbated poverty in rural Mexico. After NAFTA went into effect, U.S. corn flooded Mexico, depressing prices for Mexican farmers trying to sell their corn. NAFTA promoters had expected Mexican farmers to switch to other crops for export; instead many exported themselves north of the border where they could earn cash and send it back home to their families.

Remittances from Mexican immigrants in the United States to Mexicans back home have risen from 7 billion dollars in 2000 to 14 billion dollars in 2004. Immigration to the United States is inextricably linked to poverty south of the border. Immigration reform cannot ignore this fact and expect to succeed.

There also needs to be more discussion of problems in our present immigration system. There are people who enter the country legally but lose their legal status despite their efforts to complete the requisite forms and follow the prescribed procedures.

On a more personal level, the immigration debate needs to keep in mind the humanity of all people, including so-called “illegal aliens.” A question that can be reasonably asked of those who decry illegal border crossings is “What would you do if you made less than a dollar a day? What would you do if your family did not have enough to eat?” Would you risk crossing the border illegally in order to help your family survive? Most of us, if we are honest with ourselves, would answer that we would cross the border or do what was necessary to feed our family.

Congress may have failed to act on immigration, but the issue is not going away. More dialogue is needed and more leadership – leadership that will seek not to divide but unite Americans in a common cause of fixing our broken immigration system.