Oops! Ted Cruz unwittingly makes a powerful argument for 'amnesty' while bashing Rubio

Ted Cruz's campaign is out with a devastatingly effective ad attacking Marco Rubio on immigration. Its killer crescendo features short clips of Rubio and Barack Obama echoing the same points about comprehensive immigration reform.

Speaking of the “gang of eight” comprehensive immigration reform bill Rubio sponsored in 2013, Obama and Rubio lay out some of the hoops that undocumented immigrants would have to jump through in order to gain legal status...

Rubio: They'd still have to qualify for it, meaning...

Obama: ...passing a background check...

Rubio: ...pass a background check...

Obama: … paying a penalty...

Rubio: … pay a fine...

Obama: … paying taxes...

Rubio: … start paying taxes...

Obama: … it won't be a quick process...

Rubio: … that is a long path...

Obama: … but it will be a fair process...

Rubio: … but I do think it's fair.

The ad concludes with an ominously voiced tag-line: “Marco Rubio burned us once. He shouldn't get the chance to sell us out again.”

It's hard to imagine Cruz coming up with a more effective attack for a Republican primary audience. The ad not only makes a mockery of Rubio's claim that he would never support a bill that includes “amnesty” – which is how conservatives characterize the Gang of Eight's winding “path to citizenship” – but it also paints him as an establishment toadie who's willing to cut deals with the Kenyan Interloper.

But there's a certain irony to this spot: If advocates of comprehensive immigration reform were granted one wish, it would be that every American knows that a path to citizenship is a long process that entails passing a background check, paying a fine and forking over any taxes they owe – the precise message that Ted Cruz's campaign is now paying to broadcast.

For the past ten years, polling on immigration policy has been quite stable. Only a small minority of anti-immigrant hard-liners think we should round up 11 million people and deport them. But it's also true that most Americans don't believe that people who are here illegally should get a free pass.

Ten years ago, Ruy Teixeira surveyed a bunch of polling data and concluded that “the public favors a tough, but not punitive, approach to the problem of containing illegal immigration and is willing to consider fairly generous approaches to the illegal immigrants already here, provided they feel expectations for these immigrants are high.” That remains true today. In poll after poll, only a minority of respondents say they support “amnesty,” but when you call it a “path to citizenship,” it gets majority support. And when you explain what that path entails, large majorities of Americans, including Republicans, give the idea a thumbs-up.

An NBC News/ WSJ poll released in November of 2014 found that simply adding the words “with penalties” after “a path to citizenship” increased support for the proposal from 59 percent to 74 percent. And an ABC News/ Washington Post poll released last summer found that adding “if they pay a fine and meet other requirements” increased respondents' support for allowing undocumented immigrants to live here legally from 46 percent to 60 percent.

Cruz is vying for the support of immigration hardliners – including the 17 percent of Americans who think we should round up the “illegals” and send them packing. It's a good strategy in a Republican primary. But if this attack on Marco Rubio gets a lot of play -- and it is already generating some media buzz -- then it should reach a larger audience, and it might just teach them a thing or two about what a “path to citizenship” really means. And that's ultimately a good thing for immigration reform's long-prospects.