New Jersey Gov. Chris Christie announced yesterday that he was halting work on an $8.7 billion rail tunnel under the Hudson.  Here’s why:

The federal government and Port Authority of New York and New Jersey ultimately each pledged $3 billion. But New Jersey, which had committed $2.7 billion to the tunnel, was responsible for anything over that.

And “anything over that” was ballooning before the digging even began.  Christie was faced with estimates of final costs ranging from $11 billion to $14 billion, implying the state’s $2.7 billion share could double or triple, and Governor Awesome made an adult decision.

Yes, it would be rilly rilly rilly nice to double the rail capacity between New Jersey and Manhattan.  Yes, the construction jobs would would be good for the economy and the increased rail capacity would boost housing values.  But the construction money has to come from somewhere, the state already is in a deep financial hole, and I was pleased but not surprised that Christie pulled the plug.

Then I was surprised but not pleased to hear, one day later, that the governor was waffling on the decision, after a meeting with federal Transportation Secretary Ray LaHood.

“The fact that the ARC [Access to the Region’s Core] project is not financially viable and is expected to dramatically exceed its current budget remains unchanged,” Christie said in a statement Friday. “However, this afternoon Secretary LaHood presented several options to potentially salvage a trans Hudson tunnel project. At the secretary’s request, I’ve agreed to have executive director of NJ Transit Jim Weinstein and members from his team work with U.S. Department of Transportation staff to study those options over the next two weeks.”

However this turns out, the waffling reflects badly on the Republican governor.  I generally have little use for Democratic Sen. Frank Lautenberg, but I can’t argue with his statement today:

“Why we couldn’t have talked five weeks ago, or six weeks ago, I don’t understand.”

(The “we” is a nice touch — as near as I can tell, the Senator wasn’t actually in the meeting, he just went running to find a camera afterward.)

I don’t understand why Governor Christie would jeopardize his hard-won reputation for standing firm in the face of intense pressure. Presumably we’ll know more about what happened within a couple of weeks.