Republican Presidential candidate Ted Cruz stands along the United States border with Mexico as he speaks to Cochise County Sheriff Mark Dannels and Arizona State representative David Gowan near Douglas, Arizona. (Sam Mircovich/Reuters)

Sen. Ted Cruz toured the Southern border Friday, accusing federal officials of lax enforcement and challenging Donald Trump’s views on immigration.

Cruz was driven along the border at a remote ranch here that was studded with sagebrush and mesquite trees. Clad in sunglasses, jeans and cowboy boots, he stood by a low fence separating the countries.

“My 5-year-old could climb this in about three seconds,” he said.

“There’s no barrier at all a couple miles down,” Cruz said, looking along a dirt road.

Cruz’s trip here is a way for him to project toughness on immigration as he tries to take on Trump ahead of this state’s presidential primary Tuesday. Trump, who is leading in polls here, has made immigration his signature issue, vowing to build a wall along the border and make Mexico pay for its construction.

Here in Arizona, Trump has been endorsed by Maricopa County Sheriff Joe Arpaio, an immigration hard-liner, and former governor Jan Brewer (R).

This state has been at the center of the country’s battles over illegal immigration, and it is no surprise that the issue is playing such a prominent role in its presidential primary. Brewer signed a bill in 2010 that required the police to determine the immigration status of someone who is arrested or detained if the person is suspected of being in the country illegally; the Supreme Court struck down parts of the law. In July, Trump held an immigration-focused rally here at which he said undocumented immigrants “flow in like water.”

Cruz has long taken a tough stance on illegal immigration, and he has spent the past few years criticizing a failed immigration reform bill that would have granted undocumented immigrants a path to citizenship, something he calls “amnesty.” But he has significantly sharpened his tone on immigration since Trump came into the race for the Republican presidential nomination, stating in February that if he is elected president, he will find and deport the 11 million people thought to be living in the country illegally.

Cruz continued to paint Trump as taking an expedient view of immigration, accusing him of hardening his stance when he decided to run for president after bankrolling senators who sponsored the failed immigration bill.

Cruz was briefed at the border by Cochise County Sheriff Mark Dannels and Arizona House Speaker David Gowan (R), who told Cruz about drug smuggling across the border and a shootout at one crossing. A helicopter hovered overhead.

“What’s the volume of traffic you see coming across here?” Cruz asked Dannels.

Tracking the race to the Republican nomination

“It’s constant. It’s constant,” Dannels said.

The group was directly across the border from Agua Prieta, Mexico. Cruz was also joined by ranchers from the area and by Steve Ronnebeck, an Arizona man whose son was killed, allegedly by an undocumented immigrant.

“This is a national security crisis. And it’s a crisis that the federal government is refusing to do its job and solve,” Cruz told reporters, standing behind a lectern anchored in the dirt, the Chiricahua Mountains visible behind him. Cruz was flanked by former Texas governor Rick Perry and local law enforcement personnel and ranchers clad in cowboy hats. Cruz said he thinks the federal government should be working in concert with local law enforcement to secure the border.

Cruz was supposed to make a trip to the border last July with Trump, when the two were on good terms and Cruz was drafting behind the real estate tycoon in an attempt to inherit his voters, but he could not make it because he had to be in Washington for votes in the Senate.

At the time, Cruz effusively praised Trump for bringing the issue of illegal immigration to the fore and brushed off caustic comments that Trump had made about illegal Mexican migrants.

Cruz wants to strengthen border security, increasing the number of troops that patrol the border, as well as build a fence and increase the number of aircraft patrols along the frontier. He unveiled an immigration plan in November that calls for new limits on legal immigration — a shift from his previous position — and a crackdown on illegal immigration. Cruz also has called for an end to sanctuary cities and has said he does not think undocumented immigrants should get legal status.

“President Obama tells us the border’s secure. Well, I invite him to move the White House down to the Southern border. Let’s see how secure it is,” said Cruz, who has long criticized President Obama’s executive actions on immigration, vowing to repeal them if he becomes president.

“I think most Americans, when we look at immigration, follow a very basic principle: Legal good, illegal bad,” Cruz said.

Utah also holds a caucus Tuesday, and Cruz thanked former Massachusetts governor Mitt Romney, who has a home in Utah, for saying he will caucus for Cruz as a way to stop Trump.

“Listen, in my book, when someone says, ‘I’m voting for you, and I encourage everyone else to vote for you,’ that’s pretty darn good, and I’ll take that and take that happily,” Cruz said.

He also responded to a tweet from Trump that said, “Mormons don’t like LIARS.”

“Now I’m sure the LDS community appreciates Donald Trump’s advice on how to practice their faith,” Cruz said. “I somehow suspect that advice is not grounded in years of study of the faith.”