My colleagues Steve Camarota and Ashley Webster examine the likely impact of the Hispanic vote in next week’s election, offering a turnout baseline (about one-third of adult Hispanic citizens) to judge whether Hispanic turnout is higher or lower than it’s been in the past. (The report is based on the Census Bureau survey taken in November, which asks about voting, so it may not jibe with exit polling.)

The first thing to note is that the Hispanic vote is modest in size — it’ll probably amount to about 7 percent nationwide. Hispanics comprise a much smaller percentage of voters than they do of the overall adult population because a large share (nearly 38 percent) of adult Hispanics are not citizens. Also, Hispanic citizens register and vote at somewhat lower rates than other groups.

The thing that struck me was the finding that only about 28 percent of Hispanic voters are (naturalized) immigrants and just 14 percent of Hispanic voters live in the same household as a non-citizen — which may explain why immigration isn’t all that high a political priority for them. (The Pew Hispanic Center found that Hispanics rank the issue fifth in importance, behind education, jobs, health care, and the budget deficit.)

But while most of today’s Hispanic voters don’t have direct personal experience with immigration, an amnesty could fundamentally change that by adding millions of illegal Hispanic immigrants to a population of voters that right now is overwhelmingly U.S.-born. There are now only about 10 million Hispanic voters, so an amnesty for 11 million illegal immigrants, 80 percent of whom are Hispanic, could have a huge impact on the composition of Hispanic vote. Immigrants of any kind inevitably will view the immigration issue differently from people born in this country. But even more important, these new voters would all be former illegal immigrants, so the get-tough approach that so appeals to conservative and moderate voters could alienate a large share of amnesty beneficiaries once they become voters in a way that it doesn’t alienate, say, Susana Martinez.

An amnesty will help transform the Hispanic electorate into what amnesty advocates imagine it to be — a group of voters intensely interested in open immigration and lax enforcement. The open-borders folks understand this, and it’s a major reason they push so hard for amnesty. Why can’t Republicans understand it?