EL PASO, Texas (CNN) -- President Bush traveled to his home state of Texas on Tuesday to tout his new push to crack down on illegal immigration from Mexico.The president says he wants to "harden" the southern U.S. border and to implement a program for Mexican guest workers that critics say is a form of amnesty.Bush toured the U.S.-Mexico border at El Paso, which sits across the Rio Grande from the Mexican city of Juarez -- where many people enter the United States illegally each year. (Watch Bush try to wrangle tough issues on the border -- 2:40)"We're adding infrastructure to make the cities secure as well as the rural parts of our border secure," Bush said during a news conference."You're seeing a combination of fencing, cameras -- infrared -- and border patrol agents all doing their job."During a similar event Monday in Arizona, Bush announced his new push. "The American people should not have to choose between a welcoming society and a lawful society," Bush told customs, immigration and border patrol officers at Davis-Monthan Air Force Base. "We can have both at the same time."Bush endorsed building more jail cells to hold those caught inside the United States illegally, speeding up deportations, cracking down on fraudulent papers and "hardening" the border with additional officers, fences and monitoring devices."Securing our border is essential to securing the homeland," he said.Bush also urged Congress to back his proposal for a temporary-worker program, a long-standing idea he said would match legal immigrants with employers "to fill jobs that Americans will not do." But he said the program would not provide a path to citizenship for those who entered the country illegally, saying that doing so would encourage other would-be migrants to cross the border."I support increasing the number of annual green cards that can lead to citizenship," Bush said. "But for the sake of justice and for the sake of border security, I'm not going to sign an immigration bill that includes amnesty."Bush also said he would crack down on U.S. businesses that hire illegal immigrants, saying American employers "have an obligation to abide by the law."The renewed focus on immigration follows a sharp drop in the president's approval rating, and recent polls indicate most of his fellow Republicans oppose his handling of the issue.Many of his conservative allies have criticized the guest-worker program, which they say would allow illegal immigrants to obtain legal status. Many Democrats also have opposed the proposal, which Bush first outlined in January 2004. (Full story)U.S. Rep. Tom Tancredo, an outspoken advocate of a tough stance on illegal immigration, said Bush's credibility "is on the line, big time" over the issue."People even in his own party are worried about whether or not you can really take to the bank what he tells you," the Colorado Republican said. "So the president has not only got to actually say the right stuff, he's got to do the right stuff. We've got to see action on top of words."But one GOP analyst has warned that Bush must strike a delicate balance by talking tough on border security without alienating swing voters, women and Hispanics -- the latter a group that Republicans have tried to court since Bush's first presidential campaign."Republicans are talking about solutions rather than just making a lot of noise," said Leslie Sanchez, former director of Hispanic communications for the Republican National Committee. "But with those solutions come a lot of things that can look like immigrant-bashing."White House spokesman Scott McClellan said Bush wants a "comprehensive" overhaul of immigration policy, emphasizing both border security and the guest-worker proposal. But he denied this position represented any shift in the president's focus.CNN's Elaine Quijano contributed to this report.