Tackling Trump on sanctuary cities.

• Position: Illegal Immigration

Pres. Donald Trump issued an executive order that would prevent sanctuary cities--jurisdictions that choose not to enlist local law enforcement officials to aid Federal agents in deporting illegal aliens--from receiving Federal funding.

"We may be reminded of [French diplomat Alexis de] Tocqueville's observation that one unique feature of American democracy was that its decentralized administrative structure tempered what Tocqueville referred to as the potential tyranny of centralized rule," says Clayton Gillette, director of New York University's Institute of Urban Management.

Alina Das, associate professor of clinical law and codirector of NYU's Immigrant Rights Clinic, along with Vox.com journalist Dara Lind, emphasize that there is no clear policy definition for the term "sanctuary city," and that no local government actually can prevent people from getting deported--short of, say, physically attempting to block the door to City Hall.

Rather, jurisdictions that self-identify as sanctuaries usually are ones that have adopted a policy of not requiring residents to disclose their immigration status in order to apply for city services, or that do not hold people in jails at the request of Immigration and Customs Enforcement--which they are under no legal obligation to do. In fact, because such requests do not come with judicial warrants, Das maintains, honoring them often means violating residents' 4th and 5th Amendment rights.

Plenty of people living in sanctuary cities have been--and will continue to be--deported, Lind notes, in part because of a program called Secure Communities (ended in 2014, but reinstated in Trump's executive order) that allows all fingerprints and other data collected by local law enforcement officials to be shared...