There's a reason southern Dallas has a reputation as a haven for gangs, drug dealers and thugs. Tuesday's shooting death of Dallas police Senior Cpl. Norman Smith only reinforces this bad image, deserved or not.

The reputation developed over decades of neglect, and many in our city – including its leadership – have maintained a comfortable tolerance level with the crime, degradation and enormous disparities that divide north and south.

Southern Dallas is littered with scores of dilapidated, crime- and drug-infested apartment complexes such as the one where Tuesday's shooting occurred. Police officers know it. Top city officials know it. And yet the problem persists.

Nothing will change unless City Hall dedicates itself to a new mindset of zero tolerance for these properties where criminals have no qualms about brazenly setting up shop, terrorizing residents and shooting anyone who gets in their way.

This disgusting situation is reinforced by a political system that lends support to scofflaw apartment owners. Alex Stolarski, whose Oak Wood Place apartments were the scene of Tuesday's shootout, seemed to have no problem making $5,000 donations to the political campaign of Mayor Pro Tem Elba Garcia. But when it came to spending the money necessary to keep his property up to code, Stolarski has a history of coming up short.

And it is especially irksome that Garcia continues to defend Stolarski. Rather than hold him to a higher standard, Garcia appointed him to the city's Committee on Productivity and Innovation.

That goes to the root of the problem. We've heard Garcia and Deputy Mayor Pro Tem Dwaine Caraway complain vigorously about the need to clean up their southern Dallas districts. So some of their campaign contributions don't add up. (Caraway, for example, accepted $2,000 in contributions from a controversial video-porn dealer and his wife in 2007.)

There are other ingredients. Police cannot make headway simply by swooping in on drug dealers, making a few arrests, then pulling out. The concept of "clear, hold, build" shouldn't be limited to war zones such as Iraq. Drug sweeps are fine, but if the area still faces a constant threat of criminal re-infiltration, it's time for a permanent security presence.

Police and code enforcers also need a demonstration of political guts from the City Council. Better funding and support would help, but council members also must take an unequivocal stand against slum lords, porn dealers and anyone else who seems all too content with the despicable status quo.