San Luis, Ariz. ? President Bush peered across this hot, dusty and very busy illegal crossing point on Thursday, hoping to offer conservatives balking at a broad immigration bill firsthand evidence that he’s serious about tightening the nation’s 2,000-mile border with Mexico.

He said fences would help stop people from sneaking into the United States.

The president showed off a section of the border that is seeing a rising tide of illegal immigrants and other smuggling. The United States is responding with increased manpower – including help from the National Guard – and a newly beefed-up enforcement zone that features two layers of tall fencing, a concrete culvert, floodlights, watch towers and camera surveillance.

“I think it helps to have the president out here, seeing the part of the area of the country that one time was overrun by people coming in here, that’s beginning to get settled down because of a strategy that’s being employed,” Bush said later in a packed room at the Border Patrol’s Yuma Sector headquarters about 30 miles away.

“People’s work is making a difference,” the president said. “But we do not have full control of the border.”

Bush wants a sweeping immigration overhaul that combines enhanced border security measures with a guest worker program.

President Bush waves as he rides a dune buggy driven by Rocky Kittle on a tour of the Yuma Sector of the U.S.-Mexico international border. Bush toured the border Thursday near San Luis, Ariz.

But he faces stiff resistance from conservative Republicans, particularly in the House, who prefer a get-tough approach and largely oppose a Bush-backed guest worker program, which they see as providing amnesty for criminal behavior. House legislation that passed last year would make all illegal immigrants subject to prosecution as felons.

On Thursday, he said it makes sense to put up fencing along some parts of the border.

Bush did not declare his support for either of Congress’ two competing proposals – one approved by the House that would build 700 miles of fencing and a provision in the Senate bill that would build half that. Instead, he said the decision should be up to the Border Patrol.

“It makes sense to use fencing along the border in key locations in order to do our job,” he said,

The president has talked repeatedly about the wisdom of walling the border in urban areas but has also signaled opposition to widespread fencing – which is hotly opposed by his ally, Mexican President Vicente Fox. Bush told Fox News, in one of five television interviews he granted while visiting the border to further press his message: “Whatever works.”

Bush also defended those who oppose his immigration proposal against criticism that there is an element of racism to their stance.

“I think it would be too harsh a judgment to say that somebody who doesn’t support a comprehensive immigration plan is a racist,” the president told CNN. “I don’t believe that. I do believe citizens have got legitimate concerns, realizing that parts of this border have been open for anybody who wants to come across.”

Bush’s motorcade took him to a section of 6.9 miles of fencing that guard this area, the nation’s busiest immigrant-smuggling hot spot. The president climbed up to a berm overlooking the 150-foot-wide border enforcement zone, which has recently added a new secondary fence of chain links and razor wire to a 20-foot-tall wall of corrugated metal. Guided by Border Patrol officials and Arizona Gov. Janet Napolitano, the president also reviewed a line of Border Patrol vehicles and display booths.