For all of his rock-solid conservative credentials, Texas Gov. Rick Perry may have an Achilles' heel: immigration.

Perry will undoubtedly focus his presidential campaign on Texas' relatively healthy economy and its low taxes and his record in creating jobs in the 11 years he's been governor. What he may have to explain on the stump is how illegal immigrants have contributed to that success, adding as much as $17.7 billion a year to the state gross product and enjoying such benefits as in-state tuition at public universities.

"Gov. Perry is very eager to appear tough on illegal immigration, but upon closer inspection he's part of the problem," complained William Gheen, who runs the North Carolina-based political action committee Americans for Legal Immigration. The group intends to educate conservative groups about candidates' positions on that issue.

Tea party criticism about Perry's immigration record is now appearing on activist blogs in Arizona and New Hampshire.

A 2006 state report said that the state's illegal immigrants _ 1.4 million then, 1.65 million now _ added $17.7 billion to the gross state product, and that the state came out ahead on taxes it collected versus services it provided. But local governments and county hospitals were shouldering the burden of caring for that population.

The Texas Association of Business, which has backed Perry in all his gubernatorial campaigns and has members who individually have provided Perry with hundreds of thousands of dollars in campaign cash, touted that report in its firm support of comprehensive immigration reform. TAB, the state's chamber of commerce, has lobbied for immigration reform and against state legislation regulating immigration.

"The economy would suffer without undocumented workers," said Bill Hammond, TAB president and CEO. "We need them."

Texas remains welcoming to immigrants in ways some other states are not.

Illegal immigrants can get in-state tuition at Texas universities. Neither employers nor state agencies are required to run job applicants through a federal database to determine their legal status. Illegal immigrants have access to services for drug treatment, mental health and children with special health care needs.

"Bush was a moderate on this issue and his party rejected him then," said Bruce Buchanan, a government professor at the University of Texas-Austin. "If anything it's grown more hard-edged since. It's a world of difference."

Perry insists that he has taken a strong stand on securing the border, but his rhetoric has always focused on transnational gangs and drug traffickers, not those looking for legitimate work. He points out that since 2005 the state has steered more than $400 million into border measures.

"Gov. Perry has continued to push for the federal government to fulfill their responsibilities in a number of areas including border security and illegal immigration," spokeswoman Katherine Cesinger said. "The issue with immigration reform goes back to border security ... you cannot have real immigration reform and effective immigration reform without first securing the border."

Bryan Eppstein, a Republican political consultant in Texas, said Perry is strong on the issue. He noted that Texas requires proof of legal status to get a driver's license and every county jail checks its inmates' immigration status with a federal database.

"He has approached immigration reform in a way that is best for Texas," Eppstein said. "He's done everything the leader of a state government can do and has called upon continually the federal government to address what they can address."

But when the Legislature convened its 2011 session, Perry's name was already being circulated as a possible presidential contender. For the first time in his decade-long tenure, Perry pushed a bill that would have prohibited Texas cities from acting as "sanctuaries" for illegal immigrants and would allow local law enforcement to become more involved in immigration enforcement. It failed in spite of Republican majorities in both chambers and drew opposition from some large employers.

That failure, combined with Perry's comments that the U.S.-Mexico border fence was "idiocy" and that efforts to deny citizenship to U.S.-born children of illegal immigrants are "divisive," have rung in the ears of anti-illegal immigration conservatives.

"We have not seen much at all on immigration, nothing at all," said Suzanne Guggenheim, a Texas-based member of the Tea Party Patriots National Leadership Council. "There is some disappointment" with his leadership on the issue.

The moves that Perry has made on his own to secure the border have been criticized as more flash than substance.

Perry passed $2 million in federal grants to a border sheriffs' coalition for 200 cameras along the border allowing anyone to watch through the Internet and then email reports of suspicious activity. But few of the cameras were ever installed, the ones that were didn't work, and the effort was deemed a half-hearted failure.

A program sending small teams of Texas Rangers to remote border locations to deter drug traffickers was a regular feature of Perry's speeches last year. But his administration refused to release any details about the number of rangers involved _ there were only 144 in the state _ or their drug or property seizures or arrests.

Nationally, immigration has declined as a political issue as the recession reduced the flow of illegal workers across the border. But it remains a touchstone for some conservatives. Dozens of immigration-related bills were introduced into the Texas Legislature this year, although none have succeeded.

If Perry becomes president, Texas illegal immigration opponents say, conservative voters shouldn't expect tough leadership on the issue.

JoAnn Fleming, chairwoman of the Tea Party Caucus advisory committee to the Texas Legislature, said, "We have a little bit of trouble imagining that our governor could do that on the national level."