For a state that has been largely absent from the public debate over immigration, Missouri's places, politicians and professors have been surprisingly involved in a variety of ways.

Valley Park, John Ashcroft and University of Missouri-Kansas City Professor Kris Kobach have all helped shape the current push among states and municipalities around the country to get tough on immigration enforcement.

The new environment after the terrorist attacks of Sept. 11, 2001, caused immigration — which until then had been debated largely on economic grounds — to be viewed as well through the prism of national security. That put a damper on what had been a strong push to reform the nation's immigration system.

Ashcroft, Missouri's former governor and senator, was serving in 2001 as attorney general, the nation's top law enforcement official. In that capacity, he reversed the opinions of his six immediate predecessors by telling local police they could enforce immigration laws.

This helped spread the immigration flow away from the six states that had previously received the overwhelming share and to urban areas where sentiment over immigration was less polarized and rural areas with poultry or meat-packing plants. Immigrants felt they might be less subject to scrutiny in these "quieter" places.

That, in turn, began to arouse political reaction in places unused to this phenomenon, including small municipalities and rural areas of Missouri.

As the immigration issue grew increasingly controversial, legislators in Washington couldn't agree whether to broadly reform policy or simply get tough on illegal immigration and close the borders. The resulting inaction led to frustration among some state and local authorities, who decided to take their own steps.

Hazleton, a town in Pennsylvania, acted first, followed by St. Louis County's Valley Park, whose "Illegal Immigration Relief Act Ordinance" of 2006 targeted employers who hired or landlords who rented to illegal immigrants.

The Missouri case assumed prime importance when Hazleton's measure was struck down by the courts — shining the national legal spotlight on Valley Park — and the subsequent upholding of parts of the local ordinance was a pivotal moment in the immigration controversy.

It sparked political infighting among leaders in Valley Park, led to some dramatic events, including immigrants taking refuge in a church, spawned tougher enforcement by some surrounding communities and gave rise to a variety of legal actions.

On a national level, it encouraged similar action by other communities, helping inspire in 2007 alone the introduction in state legislatures of 1,100 immigration bills — many of them restrictive in nature — and multitudes of local ordinances.

Many immigration measures, including in Hazleton, Valley Park and Arizona, were written by UMKC's Kobach, who had been a top aide in Washington to Ashcroft on immigration matters.

"There is a well-organized, well-funded effort to help states craft, and defend, immigration measures. The movement is really being spearheaded by Kris Kobach," says Richard Middleton, an immigration lawyer in St. Louis, associate professor of political science at the University of Missouri-St. Louis and adjunct law professor at St. Louis University.

After Ashcroft left office, Kobach signed on to teach constitutional law at UMKC, and from that perch he has become the "intellectual father" of much of the nationwide anti-immigration fervor in recent years, helping write legislation and ordinances from Arizona to Cherokee County in Georgia.

John Ammann, a St. Louis University law professor who led a legal fight against the Valley Park ordinance, says Kobach is "traveling around the country enticing communities to express anti-immigrant sentiment, stirring reasonable people into a frenzy."

"Tell me the borders of Valley Park are safer now than before the litigation. There wasn't a problem to begin with."