Illegal immigration advocates often cite studies that indicate illegal aliens commit less crime than citizens in the United States. However, criminal statistics from the city of Phoenix, Arizona, after dropping sanctuary city policies in 2008 completely undermine the talking point.

Los Angeles Police Chief Charlie Beck supports sanctuary policies, and explained why he believed it meant citizens would be more safe. "We do not want to dilute trust because trust is the most important thing in policing," he said. "We depend on our communities, particularly our immigrant communities to cooperate with us, not only to keep them safe but to keep all of you safe."

But according to Levi Bolton, the executive director to the Arizona Police Association, when Phoenix suspended its sanctuary city policies, instead of endangering the citizens, the opposite happened.

"We saw a decrease in crime," said Bolton. "It had a deterrent effect on folks because the risk of discovery went up exponentially when we actually enforced the law."

Under the new policies, law enforcement could ask suspects if they are in the U.S. legally, and they could inform immigration agencies about violations of federal laws.

Fox News reported that the murder rate in Phoenix fell by 27 percent, robberies fell by 23 percent, and assault fell by 13 percent. Even more minor crimes fell, with burglaries by 14 percent and theft by 19 percent.

While the causes of crime are multitudinous and could be attributed to numerous sources, illegal immigration critics find confirmation of their political beliefs in the statistics.

One study challenges the illegal alien narrative by showing that there is no connection between crime and the presence or absence of illegal aliens.

The six-year study from the University of Riverside, California, across 55 cities found "no statistically discernible difference in violent crime rates, rape, or property crime."

Curbing illegal alien crime was a promise Trump made often while on the campaign trail, and while he has not rescinded Obama's "Dream Act" for childhood arrivals, or built the border wall, his rhetoric alone has caused a steep decline in illegal border crossings.

The House of Representative also passed two bills meant to deter illegal alien crime, including the "Kate's Law" named after Kate Steinle, a victim of illegal alien crime in San Francisco.

The government in Los Angeles has been at the forefront of dissent against Trump's offensive on sanctuary city policies. In May, L.A. Mayor Gil Garcetti imposed his own executive order that extended sanctuary city policies over all city employees. The state government in California is also considering a bill to make the entire state a sanctuary for illegal aliens.