In the debate over the Postville immigration raid, a lot of people are saying, “We have to enforce our laws,” and everyone seems to take it for granted that Immigration and Customs Enforcement officials are enforcing the law. I wouldn’t be so sure. Last year’s U.S. attorney firings showed that the Bush administration is committed to politicizing federal law enforcement, and early evidence suggests that ICE might be selectively enforcing the law to help a loyal Bushie – Agriprocessors owner Aaron Rubashkin – in an organized labor fight in which neither side respects our immigration laws.

The Des Moines Register reported this week that United Food and Commercial Workers won a 2005 court battle to unionize Agriprocessors’ New York plant and is now trying to organize the Postville plant. In the 2005 fight, Agriprocessors asked a court to negate its workers’ vote to unionize because most of its workers were illegal immigrants. Managers “discovered” most of their workers were illegal immigrants immediately after the union vote, when they checked all voters’ Social Security numbers against a federal database.

It doesn’t take a genius to read between the lines. Agriprocessors officials checked voters’ Social Security numbers because they knew their workers were illegal immigrants. They wanted to overturn the vote and send a message to their next batch of illegal immigrants: If you vote to organize, you’ll be deported, but if you don’t vote, we won’t ask questions.

In its search warrant, ICE presents clear evidence that Agriprocessors officials knew they were hiring illegal immigrants. They didn’t only know in a general sense that some of their workers were probably illegal – they knew precisely which ones were illegal. Managers made illegal immigrants wear orange hardhats, while legal immigrants wore green. Illegal immigrants didn’t get employee IDs, and when one illegal immigrant asked a rabbi about it, the rabbi said he wouldn’t get an ID card until he could show valid documentation.

Agriprocessors officials also knew about and condoned rampant Social Security fraud at the plant. The human resources manager laughed when a former supervisor complained that three employees had Social Security cards with the same number. The evidence clearly shows managers and owners were complicit in the crimes their workers were committing and only pretended to care about the law when they thought it would help quash a union vote.

Of course, UFCW isn’t much better. About a week ago, the vice president of local 1149 in Marshalltown was convicted of harboring illegal immigrants, and – given their history with Agriprocessors – union officials must have known they were trying to organize illegal aliens.

Neither side of the union fight has much respect for immigration laws. The difference between the two sides is how ICE has treated them. A union official has been convicted and hundreds of Guatemalan workers have been charged but, so far, no Agriprocessors managers have been charged.

There could be innocent reasons for this discrepancy – it could take more time to collect evidence for a conspiracy charge, for example – but we shouldn’t assume the reasons are innocent. The Bush administration has a history of politicizing federal law enforcement, having fired seven U.S. attorneys who either prosecuted a Republican or didn’t prosecute a Democrat aggressively enough. The administration probably has even tighter control over ICE than it has over U.S. attorneys, given that Bush founded ICE in 2003.

Rubashkin is a Republican. He has donated over $20,000 to the Republican party, and his family members have donated some as well. Senator Charles Grassley received a total of $8,000 from the Rubashkin family. So if ICE chooses not to prosecute Rubashkin or his managers, when they have clear evidence of the managers’ guilt, we shouldn’t assume ICE is enforcing the law diligently. Instead, we should call for a congressional investigation of the Postville raid, similar to the investigation that uncovered so much impropriety in the U.S. attorney scandal.

The first man to lead the charge should be Sen. Grassley. Grassley says on his Web site that immigration is one of his pet issues and that congressional oversight of the Department of Homeland Security (which ICE is part of) is a duty he takes very seriously. I can’t think of a time when congressional oversight was more important. An entire town is flouting immigration law in Grassley’s back yard, and ICE seems to be turning a blind eye. If ICE doesn’t prosecute Agriprocessors managers, there is no doubt they will replace their workers with another batch of illegal immigrants and the raid will have accomplished nothing.

If what Grassley says is true, opening a congressional investigation into the Postville raid should be a top priority for him. If not, we will know that one of our state’s senators values $8,000 in campaign contributions more than he values his principles.