Imagine you're Ted Cruz. Things are proceeding according to plan — you're in second place nationwide and ahead in some polls in Iowa, you're consolidating the support of evangelicals, most of your opponents are falling behind or falling away, and, after treating you like a fringe figure for so long, the media is finally taking seriously the idea that you might be the party's nominee. There are only two guys standing in your way. The first is Donald Trump, and who knows what he's going to do or say. The second is Marco Rubio and, if you can take him out, it'll be down to you and The Donald — at which point even the party establishment that so despises you will probably rally to your side.
So how can you sweep Rubio aside and make it a two-man race? The answer Cruz has seized upon is immigration, Rubio's soft and vulnerable underbelly.
This tactic came out in Tuesday night's debate, when Cruz said, "You know, there was a time for choosing, as Reagan put it. When there was a battle over amnesty and some chose, like Senator Rubio, to stand with Barack Obama and Chuck Schumer and support a massive amnesty plan." He even called a bill that Rubio co-wrote the "Rubio-Schumer Gang of Eight bill," which is pretty low.
This attack isn't surprising; that Gang of Eight bill has been just waiting to be exploited. Back in 2013, Rubio joined with a bipartisan group of senators to write the comprehensive immigration reform bill, which passed the Senate and then died in the House. Even though the bill had a lot of what Republicans wanted, Rubio was immediately excoriated by the very Tea Partiers who had championed his election in 2010, called a traitor and an alien-coddler because the bill included a path to citizenship for undocumented immigrants. Rubio has since distanced himself from the effort, but it clings to him still.
Why is it such a big deal? Well, as Rubio knows, immigration is one of the main reasons so many white, older Republican voters feel out of place in a changing America. It was the subject of endless conflicts between the Obama administration and Republicans in Congress. Obama's executive actions on immigration are the evidence conservatives hold up to support their assertion that the president is a tyrant who ignores the law. Those executive actions were the cause of one of our many government shutdown crises. And it has been one of the main sources of conflict between the party establishment, which believed that the GOP needs to support comprehensive reform in order to make an opening with Latino voters and thus have a chance at winning the White House, and the base voters and conservative members of Congress who say, "Hell no." So, as complex as the issue is, it isn't hard for Rubio's opponents to say that there's a right side and a wrong side on immigration, and the senator is (or at least was) on the wrong side.
Cruz himself has been moving steadily to the right on this issue over the course of the campaign, though his precise position on the question of undocumented immigrants has at times been hard to pin down. While he has always opposed a path to citizenship, at various points he has seemed to support work permits that would allow the undocumented to stay in the country legally. This is what Rubio is referring to when he says that Cruz supports "legalization."
But Cruz is now backing away from that position, saying in the debate, "I have never supported legalization, and I do not intend to support legalization." Ask him about it now, and he'll talk only about border walls and deportation. He has even come out in favor of repealing birthright citizenship, the constitutional principle that anyone born in the United States is a United States citizen.
When he gets asked about his work on the 2013 bill, Rubio has a long, detailed answer, one he's repeated many times. It hits all the appropriate notes — slamming the Obama administration, talking about how border security must be accomplished first, noting that the E-Verify system has to be in place so employers don't hire the undocumented, and explaining the lengthy process that would be required for an undocumented person to get citizenship, a process that could take as much as a couple of decades. His basic point is that once we do all the things Republicans want, then we can get around to thinking about a path to citizenship — but it's so far down the road, it would be after he served even two terms as president.
But after Rubio gives that long, detailed answer, Cruz can just point to him and say, "Nope, he supports amnesty." Which, depending on how you define it, is true.
Had the Gang of Eight bill managed to pass the House, Rubio would have been hailed in many quarters as a hero, someone who had broken the logjam, found a solution to a complex policy problem, and delivered the GOP something it desperately needed, a chance to win over one of the fastest-growing parts of the electorate. But as it is, that 2013 bill is a millstone around Rubio's neck, one that someone like Ted Cruz is happy to pull on to make Rubio's burden even heavier.
In the context of this primary campaign, it's far better to have never tried to accomplish much of anything on policy, like Cruz. Rubio did try, and Cruz is going to make him pay. While the issue of terrorism may fade in the coming weeks and months, immigration will always be there in this campaign. And as long as they're both in the race, Ted Cruz is going to pound Marco Rubio on it without mercy, until one of these two sons of immigrants leaves the race.