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.