Do Sanctuary Cities Like Cambridge, Somerville, Protect Or Endanger The Innocent?

After an unauthorized Mexican immigrant with a criminal record shot and killed a woman in San Francisco earlier this month, the debate over sanctuary cities is back in the news in a big way.

Sanctuary cities — like San Francisco — have pledged not to cooperate with federal efforts to round up unauthorized immigrants. But following the killing, Congressional Republicans are pushing laws that would block funding for cities that provide safe harbor for undocumented immigrants.

Here in Massachusetts, there are six sanctuary cities, including Chelsea, Somerville and Cambridge. Proponents say they protect immigrants who have committed no crimes, beyond their undocumented status.

But critics say, sanctuary for the innocent is one thing. Protection of criminals is a different and troubling matter.

John Tirman, executive director and principal research scientist at the MIT Center for International Studies. He's also author of “Dream Chasers: Immigration and the American Backlash.” He tweets @JohnTirman.

Alice Wolf, former state representative and former Cambridge mayor who sponsored the original sanctuary city resolution in Cambridge in 1985.

Thomas O’Loughlin, Milford chief of police.

Cognoscenti: Undocumented Immigrants And The Paradox Of ‘Sanctuary Cities’

POLITICO: GOP Turning Up The Heat On 'Sanctuary Cities'

The New York Times: Lost In The Immigration Frenzy