Obviously, nothing ever came of the threat. But you have to wonder if San Francisco really wants to be part of the U.S. anymore.

During the Civil War, New York city threatened to secede from the union because so much of its economy was dependent on shipping exports of cotton and other products from the South.

The city refuses to help enforce immigration laws. It is so anti-military that residents actually voted to prevent the National Guard from recruiting in high schools. The city's politics are so far left that if it were any more liberal, it'd be drowning in the Pacific Ocean.

So it's hardly surprising that the city has announced that it will withdraw from the FBI's task force on terrorism, putting the rest of us in danger.

Fox News:

San Francisco has taken its defiance of the feds to a new level, ending its cooperation with the FBI in an anti-terror initiative begun after 9/11 – a move crtitics [sic] say could get innocent people killed.

Critics say the sanctuary city by the bay's latest decision to forego cooperation with Washington, by dropping out of the FBI's Joint Terrorism Task Force, could put lives at risk. The JTTF has been credited with foiling 93 Islamist terrorist attacks and plots against the U.S. since 2001, including 12 this year, according to the Washington, D.C.-based Heritage Foundation. There are another 1,000 investigations into suspected terror activity nationwide.

These staggering statistics make the recent decision by the San Francisco police department to end the city's partnership with the JTTF, at the behest of local activist groups that alleged Arabs and Muslims are wrongly targeted by the FBI and will be more so under the Trump administration, all the more concerning, said retired federal law enforcement officials.

"In my opinion, the decision by the mayor and the police chief to withdraw the San Francisco Police Department from the JTTF is really narrow-minded," said Mark Rossini, a retired FBI special agent, and founding executive of the National Counterterrorism Center, who served as a representative to the CIA's Counterterrorist Center. "Politics aside, and the mayor and leaders of San Francisco have their right to their opinion, political opinion and beliefs. But when you're working in law enforcement, law enforcement should know no politics."

The FBI leads the 104 Joint Terrorism Task Force units across the country, but the majority of intelligence about crime and terror comes from local sources, said Claude Arnold, a former U.S. Immigration and Customs Enforcement special agent in charge of Homeland Security Investigations, who worked in California.

"There is less chance of uncovering networks, plots, missing pieces of a puzzle, without cities participating in the JTTF," Arnold said.

The "let's not hurt the feelings of Muslims" narrative could end up costing American lives. And it opens an interesting possibility.

Suppose San Francisco is hit by a mass-casualty terrorist attack. Why should the rest of the country help it recover? When it gives what amounts to an open invitation to terrorists to hit the city, why should the rest of us indulge its conceits?

The same might be said if a major quake destroys much of the city. Why should the military and National Guard give San Franciscans a hand when the city fathers have done nothing except trash our men and women in uniform?

Actions have consequences. And more than any other city in the U.S., San Francisco's actions speak volumes about their rejection of the idea of collective security – except, of course, if they were to get into trouble and desperately need the rest of us to bail them out.