This blog focuses on New York. But the new managers of the Xanadu-cum- “American-Dream@Meadowlands” mall project over in Jersey noted helpfully yesterday that “Manhattan can see us.”

OK, then. What Manhattan sees today is an unwise leadership decision on the part of New Jersey Gov. Chris Christie.

Yesterday, Christie officially threw state support behind the resurrection of this long-failed project to build a mega-mall in northern New Jersey.

Having called the unfinished building “the ugliest damn building in New Jersey and perhaps America,” Christie pledged to see the supposedly private-sector project through under new ownership.

To that end, the state will offer $200 million in new financial help.

This move is wrong economically and financially.

It’s throwing good money after bad. As the Times notes, “the state has already spent, by some accounts, as much as $1 billion on financing, tax breaks and highway improvements to support the development.”

If Xanadu’s new owners, who came up with the new “American Dream” moniker, really thought prospects were stellar, they’d fund the whole thing themselves, rather than depend on the state.

More important, though, is the symbolism.

In standing with “American Dream” ‘s new developers, Christie is signalling to New Jersey voters that building a mall — to be sure, a big one, with shiny lights and a skating rink! — is somehow important to New Jersey’s future.

Here are the two main arguments for and against public-sector support of a giant mall:

The mall will create jobs. “The American Dream project will create more than 8,900 construction jobs over the next two years and up to 35,000 permanent jobs once it is fully operational. It is expected to attract 60 million annual visits and will generate millions in tax revenue,” his office says.

So what? Digging ditches and filling them in creates jobs. President Obama’s stimulus saved jobs (mostly in the public sector).

The question is: does the mall take away better jobs, by making true private businesses compete against a subsidized enterprise, and by taking money away from the public infrastructure — roads, transit, etc. — that the private sector needs to create its own unsubsidized jobs?

If the dozens of other political vanity projects — from sports stadiums to Atlantic Yards to Destiny USA — that came before this one are an indication, the mall will continue to be a boondoggle.

The existing unfinished mall is an eyesore. Again, so what? Half of the skyscrapers in Jersey City are kind of ugly, but no one suggests expending public money to tear them down and build something nicer.

No, it’s not pleasant to look at an ugly, unfinished building. But one would think that a historic fiscal crisis should preclude any public subsidy for beauty. New Jersey residents could put up with an affront to their refined aesthetic tastes for a little longer.

Unless the building is a threat to elf’n’safety, the private sector should sort it out. Until then, Christie should put ever-scarcer public money toward public infrastructure.