Bad news either way, as Ross Douthat says. If the threat is bogus, we’ve reached a point of fear where one crank can keep 640,000 students out of school for the day. If the threat isn’t bogus, hoo boy.

The LA Times claims that the threat was “called in” to a school board member but the NYT says it was received “electronically.”

Ramon C. Cortines, the superintendent of schools, said he would keep schools closed until the police had searched buildings to make sure the campuses were safe. Buses that had taken children to school early this morning were turned around and sent back. The threat was received electronically…

The action came as the region remains on edge after the terrorist attack in San Bernardino less than two weeks ago that left 14 people dead and 22 wounded. Over the past two weeks, there have been a number of bomb threats. This one, Mr. Cortines said, raised more concerns.

“A threat had been made to not one school but many schools in this district,” he said. “Some of the details talked about backpacks and other packages. After talking with him, also with the board president, I made a decision to close all of the schools.”

The calculus here is the same for an asteroid strike: Low risk but huge consequences if it pans out. The odds that someone planted bombs in multiple schools without being noticed is tiny, although not as tiny as it was before we found out recently that an honest-to-goodness jihadi was inspecting schools for a California city’s environmental agency. Imagine if the school board, knowing the risk, took a gamble that the threat is phony and let kids come to school — and then bombs started going off. L.A. would never be the same.

So they traded a low-risk/high-cost scenario for a high-risk/low-cost one, namely, that there are bound to be copycat threats now. What do they do the next time someone sends an e-mail claiming that multiple schools are wired?

And what exactly made this threat “credible”? Is there anything apart from the fact that there was a terror attack in California a few weeks ago, and that one of the terrorist’s accomplices has been quoted as saying there are “sleeper cells” around? Stand by for updates.

Update: Per the Times, L.A. has 900 schools plus another 187 charter schools. The LAPD’s going to search all of those today?

Update: Don’t forget, not only did Syed Farook inspect schools, he reportedly had photos of at least one (in Rialto, California) on his cell phone. Was there some evidence in the threat that the person who sent it knew Farook and might be an undiscovered accomplice? How often do jihadis phone in threats before they strike?

Update: Fox News is citing a L.A. school spokesperson as saying the threat came from an IP address in Germany.

Update: A statement from Democratic Rep. Brad Sherman, who represents a district in L.A.:

“I have reviewed the email that was sent to a Los Angeles school board member.

“The author claims to be an extremist Muslim who has teamed up with local jihadists. We do not know whether these claims are true or a lie. We do not know whether this email is from a devout Muslim who supports jihadists or perhaps a non-Muslim with a different agenda.

“The email makes relatively specific and wide raging threats to Los Angeles schools. We do not know whether some or all of the threats are truthful.

The only thing we know is that the email was sent by an evil person.

“We also know what the LA school board has taken the strongest possible action to protect student safety.”

“The text of the email does not demonstrate that the author has studied Islam or has any particular understanding of Islam.

Update: Did L.A. get the same threat that New York got? Because this … doesn’t sound all that credible:

“I think the initiator, the instigator of the threat may be a ‘Homeland’ fan, basically watching ‘Homeland’ episodes that it mirrors a lot of recent episodes on ‘Homeland,'” Bratton said…

Bratton, speaking alongside New York City Mayor Bill de Blasio hours later, said officials in New York had reviewed an email that appeared to be sent from overseas and determined it was a “hoax.”

The email was received by a New York superintendent early Tuesday, Bratton said, adding that one indication it was a hoax was that it did not spell Allah with a capital “A.”

De Blasio described the threat as generic and implausible, and said it was sent to numerous school districts nationwide.