Seeking sanctuary, or defying federal law?

There are now 340 sanctuary cities — and the list is growing. All choose to ignore federal immigration law by refusing to report detained undocumented immigrants to federal authorities under most circumstances.

Partly as a result, deportations of those who entered the U.S. illegally are at a 10-year low — even according to the Obama administration’s new rigged redefinition of deportation as also occasionally preventing illegal entry at the border.

Some of the 1,000 undocumented immigrants who go unreported to federal authorities each month and are thereby shielded by sanctuary cities from deportation have been accused of violent crimes. According to a new report by the Center for Immigration Studies, more than 2,000 of the immigrants released have used their freedom to commit crimes.

Last year, San Francisco released from its custody 252 undocumented immigrants whom federal authorities had asked the city to hold, according to the report. Most notoriously, the city protected Juan Francisco Lopez-Sanchez — five times previously deported, seven times convicted of felonies — who now is accused of killing 32-year-old Kathryn Steinle in front of witnesses.

The Obama administration’s record on illegal immigration is little better than that of sanctuary cities. The Department of Homeland Security has told Congress that from 2010 to 2014, U.S. Immigration and Customs Enforcement released 121 undocumented immigrants who had committed crimes and were later charged with homicide.

In 2013 alone, ICE released more than 36,000 undocumented immigrants with criminal convictions. One thousand of them were charged with committing subsequent crimes, according to the Center for Immigration Studies report.

Why have these sanctuary cities and an agency overseen by the Obama administration chosen to disregard federal law and risk the safety of the public?

First, a Republican-majority Congress is unlikely to repeal immigration statutes. That means an amnesty agenda must be carried out in defiance of the law by city authorities sympathetic to illegal immigration, with a wink and from the Obama administration.

Second, the administration presumably envisions minorities voting in bloc fashion for the Democratic Party at election time.

Third, cities are generally more liberal than the country at large. There are no political downsides for high-ranking city officials who choose to disregard law.

In the 19th century, the Supreme Court issued a number of rulings prohibiting states from ignoring federal laws. The most prominent nullificationist was Sen. John C. Calhoun, a South Carolina states-rights advocate. Calhoun declared, for example, that federal tariffs should not apply to his state.

Apparently, sanctuary cities do not understand the illiberal pedigree of federal nullification, which was at the heart of the Confederate secessionist movement of 1861. In the 1960s, segregationists declared that Supreme Court decisions and integration laws did not apply to their states. In some states, law enforcement refused to cooperate with federal authorities to integrate schools.

Sanctuary cities remind us that the obstacle to supposed comprehensive immigration reform is not opposition from intolerant conservative bogeymen.

So where do we go from here?

If immigration law were nullified, almost anyone could enter the United States. Perhaps undocumented immigrants from Asia would soon outnumber those from Mexico and Central America. And if cities can declare supposedly conservative federal immigration law invalid, then some states might do the same, deeming lots of federal statutes too liberal.

I thought the Civil War ended these dangerous ideas for good.

Why have these sanctuary cities and an agency overseen by the Obama administration chosen to disregard federal law and risk the safety of the public?

Victor Davis Hanson is a syndicated columnist.