Despite the shorthand language used in the current immigrant uproar, there are no true "sanctuary cities."
And President Donald Trump sounds far from ready to spitefully ship thousands of migrants arrested at the southern border to places that bear the name.
The phrase "sanctuary cities" misleadingly suggests that immigrants to the U.S. without papers can move to New York City, San Francisco or Los Angeles and arrogate the rights of citizens.
The impact is way more limited than that.
These cities and other local governments are mainly forcing federal officials to work harder to raise their numbers for catching and deporting the undocumented. New York City, for example, makes Immigration and Customs Enforcement get a judge's authorization if they wish to nab somebody from a local jail who has committed a crime.
A group that supports a hard line, the Center for Immigration Studies, defines the sanctuary phrase this way:
"These cities, counties, and states have laws, ordinances, regulations, resolutions, policies, or other practices that obstruct immigration enforcement and shield criminals from ICE."
They do this "either by refusing to or prohibiting agencies from complying with ICE detainers, imposing unreasonable conditions on detainer acceptance, denying ICE access to interview incarcerated aliens, or otherwise impeding communication or information exchanges between their personnel and federal immigration officers."
Those in sanctuary cities don't seem to really enjoy sanctuary, however.
For example in December, ICE figures showed New York area arrests up 35 percent over the previous year for a total 3,476. About 64 had criminal records, which is proportional to national trends, The Gothamist website reported.
In February, the city's comptroller, Scott Stringer, said the number of people without criminal convictions deported from the five boroughs jumped to 1,144 during Trump's full fiscal year in office, compared with 313 during the final year of President Barack Obama's term.
One could even say the term "sanctuary cities" gives self-styled lefties in municipal governments way too much credit among their fans by overrating the defiance and sweep of their policies.
Immigration is still, as always, a federal domain.
"Sanctuary cities" echoes the religious and political sanctuary movement of the early 1980s that sought to give safe haven to Central American refugees fleeing civil conflict who found legal asylum difficult to get.
Trump uses the phrase to keep his voter base interested.
"We'll bring (refugees) to sanctuary city areas and let that particular area take care of it, whether it's a state or whatever it might be," Trump told reporters Friday.
But his spokeswoman Sarah Huckabee Sanders kept the responses soft when pressed over the weekend.
"Certainly, we are looking at all options," she told Fox News. "Nobody thinks this is the ideal solution, but until we can fix the crisis at the border, we have to look at all options."
Chances are this will end, like other noisy Trump threats, without consequence. He's talked of closing off border crossings, of cutting off all aid south of the border, of new car tariffs on Mexico, and of ending law-enforcement grants to sanctuary cities. And he isn't bringing back family separations, which proved a political fiasco when tried.
"Sanctuary cities" has been a rallying cry in Republican debates for more than a decade, since these places are usually Democratic-run. In ex-Mayor Rudy Giuliani's failed run for president in 2008, he drew debate fire from the likes of now-Sen. Mitt Romney (R-Utah) and the late Sen. Fred Thompson for running a "sanctuary city."
In fact, the GOP mayor in 1996 sued the Clinton administration over a new law that said states or cities couldn't stop employees acting on their own from turning over information about illegal immigrants to the federal government. Giuliani lost in court.
“If we didn’t allow illegals to report crimes,” the presidential-lawyer-to-be complained in 2007, “a lot of criminals would have gone free because they’re the ones who had the information." The policy preceded his administration.