On Fox News Sunday, Scott Walker admitted under questioning that he had changed his position on whether undocumented immigrants should eventually have a path to citizenship. “My view has changed,” he said, “I’m flat-out saying it.” Walker is now against “amnesty,” and insists that the first priority is to “secure the border.” Which makes him like most Republicans who run for president, not only in the fact that “Secure the border!” will be the first thing he says whenever the subject comes up, but also in the fact that his position has shifted in response to the electoral calendar.

This plot has been repeated so many times before that it’s a wonder we treat it as anything more serious than the fictional portrayal of a policy discussion that it actually is. We sat through it with John McCain in the lead role, then Mitt Romney, and now the current slate of candidates. The progression is always the same:

Act 1: We should have comprehensive immigration reform. This is what future candidates say when the next presidential election is still a few years away. They will talk about dealing with the millions of undocumented immigrants already in the United States, and acknowledge that deporting them all is impossible. They will even sound compassionate notes about them, particularly the children. A few, like John McCain in 2005 or Marco Rubio in 2013, may even write comprehensive reform bills.

Act 2: Secure the border first! As primary season approaches, the candidates realize that the Republican primary electorate isn’t interested in comprehensive reform, and in order to appeal to them, it’s necessary to demonstrate toughness and strength. In the process of doing so, some will actually switch their positions on specific details or legislation (both McCain and Rubio declared their opposition to the bills they themselves wrote; Mitt Romney went from advocating a path to citizenship to supporting “self-deportation”), but all will say that before we do anything else, we must “secure the border.”

Act 3: Can we talk about something else? Once the general election arrives, the Republican nominee will make a fruitless attempt to stop his hemorrhaging among Latino voters by changing the subject. If pressed, he will say that, of course, he supports comprehensive reform, and border security is an essential part of that — in other words, begging both conservatives and moderates not to be too mad at him for the positions he took at various times before.

It’s important to understand that almost all of the current Republican candidates have gone through Act 1 and are now in Act 2. While they may vary in the vehemence with which they decry illegal immigration, if pressed they’ll say that eventually we could have a pathway to some sort of legal status for the undocumented (as the conservative Daily Caller recently put it, “By Standards of Immigration Hawks, All 2016 Contenders Support ‘Amnesty’“). But now it’s all border security first, which as Greg pointed out on Friday, even Jeb Bush, supposedly the strongest advocate of comprehensive reform, has embraced. And while it hasn’t been much noted, Bush has shifted his position, too: he used to favor a path to citizenship for undocumented immigrants, but now he favors only a path to some legal status that would allow those immigrants to work legally but wouldn’t allow them to become citizens.

In this utterly predictable progression, there are a few realities none of the candidates will admit. The first is that “Secure the border first!” is an utterly hollow position, because it’s never followed by any specificity about how we’ll know when the border is “secure.” So long as even a single immigrant can find a way in, it will be possible for Republicans to say that the border is not yet secure, so we can’t enact any of the other parts of immigration reform.

The second reality is that the border is massively more secure today than it was just a few years ago. In the last decade, the Border Patrol’s funding has doubled. There are now nearly twice as many Border Patrol agents as there were ten years ago. And the number of apprehensions at the border those agents have had to make has fallen by more than half. You can still argue that more should be done, but you can’t say that under Barack Obama there hasn’t been an increase in border security; even if the big increases started under George W. Bush, Obama has maintained them.

The final reality is that as long as Republicans control at least one house of Congress, no matter what has been done to secure the border, no comprehensive immigration bill that includes a path to legal status for undocumented immigrants will pass. That’s because House Republicans don’t want comprehensive immigration reform, nor do the constituents in the safe districts they represent. Those constituents are the same people who vote in Republican presidential primaries. For those representatives, who fear only a challenge from the right, it’s always Republican primary season.

It would be refreshing to hear the candidates acknowledge those realities, and explain how their ideas on immigration would accommodate them. But that isn’t in the script.