But even as a figure of speech, it's a despicable concept. It refers to the notion that undocumented immigrants exploit the quintessentially American policy of birthright citizenship, which confers the status of citizen to anyone born on U.S. territory, by sneaking across the border to give birth to their children.

Republican presidential candidate Jeb Bush recently stumbled into the center of a firestorm after first railing against the anchor baby phenomenon, and then clarifying himself by saying that he actually wasn't referring to undocumented Latin Americans, but rather to Asians who come to the United States as "birth tourists." In doing so, he laid bare the hard, unpleasant and racist truth behind the term.

Jeff Yang

The basis for conservatives' rage about anchor babies is the claim that they serve as protection against deportation if their parents' undocumented status is discovered and give them an advantage when seeking permanent residency or citizenship in the future.

Nothing, of course, could be farther from the case.

Thousands of deportees will attest to the fact that having a child, even an infant, who is an American citizen won't stop you from being returned to your country of origin. And any assistance a U.S.-born child might provide in acquiring legal status wouldn't come into play until that baby is of legal age herself, which means the "anchor" has a tether that, at a minimum, stretches across the span of two decades -- hardly the kind of instant safe harbor anti-immigration advocates are implying.

The Republican Party's hostility toward Hispanic border-crossers is well-known, despite the fact that studies of the fiscal impact of immigration indicates that undocumented arrivals have little negative effect on local or national economies and may serve as a net positive stimulus. But it's hard to see how the small number of affluent Asians who have the means to come to this country by plane and give birth in luxurious spa-like settings could be a drag on American growth.

Far from it: These jet-setting mothers bring their U.S. citizen babies back home to Asia, while leaving a significant amount of money behind. And the U.S. citizen scions of wealthy Asian families would not only be more likely to return to America for education later in life, but to work here, invest here and inject human and financial capital into our society, while serving as a vital bridge between cultures in a world where such connections are the key to global soft power.

The fact is, the only thing these two groups -- poor Hispanic migrants and wealthy Asian maternity tourists -- have in common is bluntly obvious: Neither group is white. And that's the reality behind the conservatives' anchor baby obsession.

It's not about money. It's not about the strain on America's social safety nets or overcrowding in American schools or any of the other excuses that have surfaced in the toxic conversation around immigration reform. No, what's pushing candidates to talk about anchor babies and the elimination of birthright citizenship is the same old thing that drives too much of the modern Republican agenda: Fear of a nonwhite nation.

Because every Hispanic, Asian and African baby born in the United States accelerates the demographic pivot, already inevitable, that turns white Americans into a minority in this country. As the Republican establishment knows, the looming arrival of that moment spells long term disaster for the party's electoral prospects if it refuses to embrace and adapt to it.

Short term, however, the base demands that its candidates fight against this future with fervent, "This is Sparta!" passion -- even if doing so exposes the racism and xenophobia that lies at the core of those demands and makes them unelectable in the general election.

As Jeb Bush must realize after his clumsy attempts to establish his conservative base and maintain his moderate facade, the hard-core nativists that make up the heart of the Republican Party are the real "anchor babies." And they're dragging Republicans down into the swamp of irrelevance.

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