There really aren’t any major issues on which Mitt Romney has been consistent, but given the zeal with which he’s moved to the far-right on immigration, revelations like these seem rather noteworthy.

Former Massachusetts Governor Mitt Romney, who charged Republican presidential primary rival Newt Gingrich with proposing “amnesty” for certain illegal immigrants, took a nearly identical position in a 2006 Bloomberg interview, saying some foreigners who entered the U.S. illegally should be allowed to remain and gain legal status.

Romney, who at the time hadn’t yet declared his first presidential candidacy for 2008, told reporters and editors in Bloomberg News’s Washington bureau that the 11 million immigrants who entered the U.S. illegally “are not going to be rounded up and box-carred out.” Law-abiding people who pay taxes, learn English and don’t rely on government benefits should be allowed to “get in line” to apply for citizenship, he said.

“We need to begin a process of registering those people, some being returned, and some beginning the process of applying for citizenship and establishing legal status,” Romney said during the March 29, 2006, session.

At the time, Romney added, in reference to undocumented immigrants already in the United States, “We’re not going to go through a process of tracking them all down and moving them out.”

This original Romney line sounds awfully similar to what Newt Gingrich said last week — and Romney condemned Gingrich’s approach.

Now, this would ordinarily be the point at which Romney’s rivals for the Republican nomination pounced, expressing outrage over the contradiction between the old Romney and the new Romney, and doing their very best to turn this into a big story. This Bloomberg News story is exactly the sort of thing a campaign’s rapid-response team should be all over.

But if recent history is any guide, the other GOP presidential candidates just aren’t willing to go after Romney with any enthusiasm. I thought, for example, the Republican field would go berserk when we learned that Romney supported taxpayer-funded abortions, but they didn’t seem to care.

I also thought the GOP field would be apoplectic when we learned that Romney had promised center-left activists he would “act as essentially a sleeper agent within the Republican Party, adopting liberal stances, rising to national prominence, and thereby legitimizing them and transforming the Party from within.” But the other Republican campaigns let it slide.

I assumed the GOP field would go crazy when we learned that Romney’s health care program in Massachusetts uses taxpayer money to provide medical care to undocumented immigrants. But the other Republican campaigns didn’t bite on this, either.

I thought the GOP field would pounce immediately on revelations that Romney’s policy team advised the Obama White House on how best to shape “Obamacare.” But, again, the other Republican campaigns said nothing.

I thought Romney would be slammed repeatedly for his support of health care mandates. And his support for gun control. And his record supporting gay rights. And his belief in climate change. Sure, he’s flip-flopped on all of these issues and more, and has become something of a far-right extremist, but at one time, Romney was practically a liberal — a detail that might matter to some Republican primary voters.

And yet, with five weeks to go before the Iowa caucuses, there are no Republican attack ads targeting Romney airing anywhere in the country. Is the Republican field simply incompetent, or are they letting Romney win?

Our ideas can save democracy... But we need your help! Donate Now!

Steve Benen

Follow Steve on Twitter @stevebenen. Steve Benen is a producer at MSNBC's The Rachel Maddow Show. He was the principal contributor to the Washington Monthly's Political Animal blog from August 2008 until January 2012.