Yesterday Paul Krugman, the Times columnist, Princeton professor and Nobel laureate, wrote a column about Romney peeling off wealthy backers from Obama and said they were leaving Obama because of his economic policies:

according to them, it’s because he “demonizes” business — or as Mitt Romney put it earlier this week, he “attacks success.” … Needless to say, this is crazy…. they also insist that their perception that Mr. Obama doesn’t like them is at the root of our economic problems. Businesses aren’t investing, they say, because business leaders don’t feel valued…This, too, is crazy

But one issue that is separating Obama from some former backers, including Daniel Loeb, who held a big Romney fundraiser with Ron Perelman two weeks back, is his perceived hostility to Israel. Loeb now funds the Emergency Committee for Israel, which bashes Obama all the time.

That is the reason Romney is holding a fundraiser in Jerusalem next week: he is demonstrating his Israel bona fides, and trying to light a fire under Obama donors. As the Wall Street Journal put it a year ago:

Jewish donors and fund-raisers are warning the Obama re-election campaign that the president is at risk of losing financial support because of concerns about his handling of Israel.

Or as John Heilemann of New York Magazine said on Hardball, Obama has alienated “a lot of Jewish donors,” because of his Israel policy. ”It is a real problem,” Heilemann said. “[B]ack in 2008… the core of his support of the financial community, the core of his support in terms of fundraising was Wall Street donors… He can’t afford to lose any major bundler support…”

Israel is obviously a factor in the big-money defections. How large a factor I don’t know. This is surely one reason Jewish Democrats are trying to position Obama to Romney’s right on the issue— because rich Jews who donate on the basis of Israel are so conservative. Krugman has the ability to call some of these folks; but he won’t go near the subject. Why not? Because he would have to open the door on the role in our politics of inflexible Jewish support for Israel’s inflexible policies.

Krugman explained it himself back in April in a mild defense of Peter Beinart (emphasis mine):

The truth is that like many liberal American Jews — and most American Jews are still liberal — I basically avoid thinking about where Israel is going. It seems obvious from here that the narrow-minded policies of the current government are basically a gradual, long-run form of national suicide — and that’s bad for Jews everywhere, not to mention the world. But I have other battles to fight, and to say anything to that effect is to bring yourself under intense attack from organized groups that try to make any criticism of Israeli policies tantamount to anti-Semitism.

So he obfuscates.