Marco Rubio’s robotic gaffes heard and heard and heard around the political world have been pored over since Saturday. But they’re a part of the pattern of code words Rubio has been raising to touch on President Obama’s race and our nation’s changing (and to Republicans, threatening) demographics.

One unsatisfying aspect of the debates has been that candidates utter ambiguous phrases and then wriggle off the hook. (Think Ted Cruz and “carpet bomb.”) Rubio’s debate bungle arose when he was navigating the tricky problem of being a young, charismatic, inexperienced senator without reminding Republican voters of Barack Obama.

The New York Times covered that dynamic today. In the debate, Rubio repeated a version of “And let’s dispel once and for all with this fiction that Barack Obama doesn’t know what he’s doing. He knows exactly what he’s doing.” Yesterday he renewed ownership of that argument, by returning to another pre-programmed attack often seen in the debates. Rubio told Londonderry voters:

I’m going to say it again. . . . Barack Obama is the first president, at least in my lifetime, who wants to change the country. Change the country — not fix it. Not fix its problems. He wants to make it a different kind of country.

I’m surprised Rubio hasn’t been called on the dog whistle rhetoric. What, exactly, does change the country mean. Not fix it, but change it? If you fix something (Rubio approves of fixing) isn’t that a change?

Change means something more sinister, without saying anything specific. It means a president who was not born in this country, and who is likely a Muslim. It means immigrants. In a party that is nearly all white, it gives passage from the son of Cuban refugees to ruminate upon whatever they detest about change.

To be fair to Mr. Rubio, the Times also reports that Mr. Rubio answers the experience question by distinguishing himself from Obama with “It’s his ideas that do not work.” In the January 14 debate, he extended his argument: “But in 2008, we elected a president that didn't want to fix America. He wants to change America. We elected a president that doesn't believe in the Constitution. He undermines it. We elected a president that is weakening America on the global stage. We elected a president that doesn't believe in the free enterprise system.”

The January 14 statement challenges ideas but it is also couched in foreignness – the president does not believe in the Constitution? Wouldn’t it be a form of traitorous behavior that Barack Obama has twice taken the oath of office? “[D]oesn’t believe in the Constitution” is saying “he’s not American.”

Rubio’s rhetoric is carefully calibrated to offer Republican voters a vessel into which they can place their deepest resentments about Obama – maybe Obamacare or guns; but also the change of having a Constitution hating African American with a suspect name in the White House.

That is why Rubio has to repeat the same lines over and over again; it’s a dog whistle with little margin for error.