CRAWFORD, Texas -- President George W. Bush has illegal immigration on his mind as he tours Arizona's border with Mexico.

Related: Video | Slideshow

Bush inspected the construction of border fencing in Yuma and talked about his push for the creation of a guest worker program and a path to citizenship for illegal immigrants.

"The reason we've come here is to show the American people that the plan that we've announced is now being implemented. And there is still more work to be done. But, nevertheless, a lot of progress is being made," Bush said.

His hope for a legislative breakthrough is complicated by cold relations with Congress, soured by the war in Iraq and a bill to extend war funding in Iraq and Afghanistan.

Still, Bush's team is privately working to rally votes and the Democratic-led Congress wants to get a new law passed by August.

But with up to 12 million illegal immigrants in the United States, lawmakers haven't agreed on how to uphold the law without disrupting lives, eroding the workforce and risking political upheaval.

To help push the deal through, Bush is talking up law enforcement changes in the hope of attracting skeptical members of his own party who have broken publicly with him over issues including border security and workplace enforcements.

The administration said there were more than 4,300 arrests in worksite enforcement cases for 2006, more than seven times the arrests in 2002.

It said it has also more than doubled border security funding from $4.6 billion in 2001 to $10.4 billion in 2007, and increased the number of Border Patrol agents by 63 percent, from about 9,000 agents at the beginning of his administration to about 15,000 at the end of 2007.

Also, the administration assigned 6,000 National Guard members to assist the Border Patrol by operating surveillance systems, analyzing intelligence, installing fences and vehicle barriers, and building patrol roads.

"I hope by now the American people understand the need for comprehensive immigration reform is a clear need," Bush said. "This problem has been growing for decades, and past efforts to address it have failed. These failures helped create a perception that America was not serious about enforcing our immigration laws and that they could be broken without consequence."