I continue to think that one of the most unsightly moments in the GOP primary came when Mitt Romney attacked Newt Gingrich for his humane opposition to deporting longtime immigrants — even as the Romney campaign refused to say whether he supports such mass deportation.

Now we have a new National Journal poll that helps explain Romney’s equivocations and contortions on the issue, but ultimately shows that Romney is even out of step with a plurality of Republicans, who support Gingrich’s position. In flirting with mass deportation, Romney was appealing only to a small far-right chunk of the electorate.

The poll finds that 43 percent of Republicans support allowing long-term illegal immigrants who have not broken any law to remain in the U.S. — Gingrich’s position. Thirty-three percent of Republicans support deporting all illegal immigrants, which is a shockingly large number, given that this would mean callously breaking up millions of families and rupturing community ties that stretch back decades. But still, more Republicans agree with Newt than with Romney, and the latter group ultimately is a small minority of Americans. Presumably Romney thinks he needs to win over that latter group in order to become president one day — hence his attack on Newt.

Meanwhile, the poll also finds that among the broader public, mass deportation of longtime illegal residents is mostly a fringe position. The largest group, or 39 percent of Americans, supports deporting some illegal immigrants but allowing longtime ones to remain, and 28 percent say all illegal immigrants should be allowed to stay if they’ve broken no laws and commit to learing English and American history. That’s 67 percent who support letting longtime immigrants remain. Meanwhile, “only” 25 percent support deporting all illegal immigrants, no matter how long they’ve been here, again a large number but ultimately a small minority.

So you can see why Romney wanted to attack Newt for opposing the mass deportation of longtime U.S. residents, while refusing to say he supports it himself: Such a position would be absolutely toxic in a general election. The obvious moral of the story is that anyone pandering in such a brazen way to a small far-right group of voters — while simultaneously hoping to appeal to the American mainstream — also needs to figure out how to avoid being directly associated with the fringe crankery those voters believe in.