President Bush heads out Monday on a two-day swing through parts of Texas and Arizona, where he will receive briefings from Customs and Border Protection personnel about the ongoing holes in border control.

Illegal immigration is a bigger subject than ever these days. Polling shows that more than 50 percent of Americans say the president is doing a good job on homeland security, and Bush's trip will include an effort to boost his overall low job approval rating by delivering a speech in Tucson, Ariz., on border security .

White House aides say the president will make remarks pledging additional resources and the use of technology to secure the border. One concept he'll discuss is "interior repatriation," a term that means returning illegal immigrants from Mexico to the interior of their country, rather than returning them just over the other side of the border.

Bush will also make another pitch for his temporary worker program, which has never really caught on in Congress.

An estimated 11 million illegal immigrants live in the United States today, up from 8.4 million five years ago. Border patrol agents arrested more than 1 million illegal immigrants last fiscal year.

The Pew Hispanic Center estimates that while about 140,000 illegal immigrants came over the border each year in the 1980s, more than 700,000 did so in 2004, primarily through the Southwestern states.

It's those numbers that leave federal officials concerned that Al Qaeda could exploit holes in the 2,000-mile border with Mexico. Rep. Peter King, R-N.Y., has sponsored legislation requiring that the secretaries of defense and homeland security cooperate on border patrols and giving the homeland security secretary expanded powers to combat the influx of illegal immigrants.

"Even if they get captured, there's no harm done, because they would be captured, and they would be released, and they can try it again. So that's why it's so important that we do detain those who are captured coming across the border, and those who are detained from countries other than Mexico, the 'OTMs, as they're called. They would be sent back to their nation of origin, and any nation that doesn't cooperate with us, we would have the right to stop their nationals from entering this country, even on a legal basis," King said.

He also explained why that idea requires the passage of a new law.

"There's always a concern that the military has, and rightly so, that they'll be overreaching. So by actually having it in law, we're putting a status on it, a legitimacy on it, which would make it entirely legal, so there's no question at all that the military is doing the right thing in working with the civilians in achieving this sealing of the borders," King said.

One group of civilians has already stepped up to the plate. The Minutemen post themselves along the border and inform U.S. agents when they see illegals making a run for it. Their efforts have gotten mixed reviews, and dismay from some official sources who say self-established scouting teams could endanger themselves and the aliens trying to cross the border.

But the Minutemen are performing the service for free. The cost of border patrol efforts has risen 58 percent since Sept. 11, 2001, and other associated costs are also adding to the burden.

Twelve years ago, the border patrol made only 10 percent of its arrests in Arizona. By 2000, that figure had risen to 37 percent. In August, Gov. Janet Napolitano declared a state of emergency in order to get federal funds to help handle the influx of illegal immigrants and the crime that followed.

At the time, Napolitano announced that the state Department of Public Safety will create a new detail of officers to work with southern Arizona law enforcement agencies to target vehicle theft, a crime often linked to transporting of illegal immigrants .

She also designated $1.5 million for four border counties' law enforcement agencies to add dozens more officers to combat other border-related crime.

That came before U.S. border patrol agents working the Arizona-Mexico border reported twice as many violent attacks in the 12 months ending in September than a year earlier.

The Yuma and Tucson sectors recorded 365 assaults on agents. Nationwide, agents were assaulted 687 times, according to the latest records. All but one of those attacks took place on the border with Mexico.

A spokesman for the border patrol told FOX News on Saturday that the escalating border violence reflects the influence of criminal gangs and the large profits made from smuggling migrants workers into the United States — as much as $2,000 per person.

"The reason for the increase is because we have a lot more agents out there. We have 2,400 agents, and we're making it a lot more difficult (to enter). We're frustrating their efforts because we have a constant presence along the borders," said border agent Jose Garza.

Law enforcement officials recently told Congress that Mexican gangs are getting more aggressive in their efforts to smuggle people and drugs, and smugglers are hiring gangs armed with assault rifles and other weapons to protect their trade.

On Tuesday, the president heads to El Paso, Texas, where he'll visit "border patrol" headquarters. In both states, he will also attend fundraisers for Republican candidates.

FOX News' James Rosen and Julie Kirtz and The Associated Press contributed to this report .