It's a classic play from the election handbook: When the going gets tough, scare the voters. Lyndon Johnson's "Daisy Girl" ad told viewers to vote or be annihilated in a nuclear war, George H.W. Bush perfected it in his Willie Horton ad against Michael Dukakis and Hillary Clinton tried it with middling success before Super Tuesday primaries with her "3 a.m. phone call" ad, designed to create doubts about Obama's experience in a crisis.

Now Rick Perry has gotten in on the action. His latest ad features Sgt. Joslyn Johnson, the widow of Houston Police Department officer Rodney Johnson, who was killed by an illegal immigrant he was arresting in 2006.

Johnson gives a few details about the murder of her husband, then claims that as Mayor Bill White presided over a "sanctuary city" with policies "that made it difficult for officers to safely do their jobs." Johnson says she supports Perry and that Bill White "failed" as mayor of Houston.

It's hard not to empathize with Johnson's situation. The loss of her husband is a tragedy, and she's entitled to her opinions. But Johnson and Perry's choice to politicize his death means we need to evaluate her claims.

Rodney Johnson was killed by Juan Quintero, an illegal immigrant who did have a history of arrests. In 1995 and 1996, he was arrested by UHD and MTA police for misdemeanor driving incidents and in 1999 he was convicted of a sex crime and deported. The next record of Juan Quintero in America was when officer Johnson pulled him over and Quintero failed to produce a driver's license. Once in Johnson's patrol car, Quintero shot the officer with a handgun he had concealed.

It's difficult to imagine what White, as mayor, could have done to prevent Johnson's death. That his second illegal border crossing must have occurred under Perry's watch is never mentioned.

It's also worth mentioning that the oft-repeated claim that Houston is a sanctuary city has been proven false. Houston police officers have been prohibited from questioning the immigration status of people involved in incidents or out in the streets since 1992, a policy begun to encourage all residents to work with police to fight crime rather than worry that calling the police could result in their own deportation.

Once a person is arrested for a crime, their immigration status is checked in conjunction with an Immigration and Customs Enforcement program and turned over to those authorities if appropriate, a program that was started during White's mayoral tenure after Joslyn Johnson sued the department.

Any departure from that policy would be inconsistent with Perry's statements in April after Arizona's controversial immigration law passed.

"Some aspects of the law turn law enforcement officers into immigration officials by requiring them to determine immigration status during any lawful contact with a suspected alien, taking them away from their existing law enforcement duties, which are critical to keeping citizens safe,” Perry said, continuing that such policies are "not right for Texas."

The real question is why Perry would run such a controversial ad so close to the election when he's already heavily favored to win.

Watch the ad below and judge for yourself:

Perry knows CultureMap's CulturePoll, in which White has racked up 78 percent of the vote compared to Perry's 21 percent, isn't official ... right?