“This was not a subject that was on anybody’s mind until I brought it up at my announcement.” — Donald Trump, on immigration, Republican debate, Aug. 6

WASHINGTON — Not on anyone’s mind? For years, immigration has been the subject of near-constant, often bitter argument within the GOP. But it is true that Trump has brought the debate to a new place — first, with his announcement speech, about whether Mexican migrants are really rapists, and now with the somewhat more nuanced Trump plan.

Much of it — visa tracking, E-Verify, withholding funds from sanctuary cities — predates Trump. Even building the Great Wall is not particularly new. (I, for one, have been advocating that in this space since 2006.) Dominating the discussion, however, are his two policy innovations: (a) abolition of birthright citizenship and (b) mass deportation.

Birthright citizenship

If you are born in the United States, you are an American citizen. So says the 14th Amendment. Barring some esoteric and radically new jurisprudence, abolition would require amending the Constitution. Which would take years and great political effort. And make the GOP anathema to Hispanic-Americans for a generation.

And for what? Birthright citizenship is a symptom, not a cause. If you regain control of the border, the number of birthright babies fades to insignificance. The time and energy it would take to amend the Constitution are far more usefully deployed securing the border.

Moreover, the real issue is not the birthright babies themselves, but the chain migration that follows. It turns one baby into an imported village.

Chain migration, however, is not a constitutional right. It’s a result of statutes and regulations. These can be readily changed. That should be the focus, not a quixotic constitutional battle.

Mass deportation

Last Sunday, Trump told NBC’s Chuck Todd that all illegal immigrants must leave the country. Although once they’ve been kicked out, we will let “the good ones” back in.

On its own terms, this is crackpot. Wouldn’t you save a lot just on Mayflower moving costs if you chose the “good ones” first — before sending SWAT teams to turf families out of their homes, loading them on buses and dumping them on the other side of the Rio Grande?

Less frivolously, it is estimated by the conservative American Action Forum that mass deportation would take about 20 years and cost about $500 billion for all the police, judges, lawyers and enforcement agents — and bus drivers! — needed to expel 11 million people.

This would all be merely ridiculous if it weren’t morally obscene. Forcibly evict 11 million people from their homes? It can’t happen. It shouldn’t happen. And, of course, it won’t ever happen. But because it’s the view of the Republican front-runner, every other candidate is now required to react. So instead of debating border security, guest-worker programs and sanctuary cities — where Republicans are on firm moral and political ground — they are forced into a debate about a repulsive fantasy.

Which, for the Republican Party, is also political poison. Mitt Romney lost the Hispanic vote by 44 points and he was advocating only self-deportation. Now the party is discussing forced deportation.

It is not just Hispanics who will be alienated. Romney lost the Asian vote, too. By 47 points. And many non-minorities will be offended by the idea of rounding up 11 million people, the vast majority of whom are law-abiding members of their communities.

Donald Trump has every right to advance his ideas. He is not to be begrudged his masterly showmanship, his relentless candor or his polling success. I strongly oppose the idea of ostracizing anyone from the GOP or the conservative movement. On whose authority? Let the people decide.

But that is not to say that he should be exempt from normal scrutiny or from consideration of the effect of his candidacy on conservatism’s future. If you are a conservative alarmed at the country’s direction and committed to retaking the White House, you should be concerned about what Trump’s ascendancy is doing to the chances of that happening.

The Democrats’ presumptive candidate is flailing badly. Republicans have an unusually talented field with a good chance of winning back the presidency. Do they really want to be dragged into the swamps — right now, on immigration — that will make that prospect electorally impossible?

Yes, I understand. The anger, the frustration, etc., etc., that Trump is channeling. But how are these alleviated by yelling “I’m mad as hell” — and proceeding to elect Hillary Clinton?

Charles Krauthammer is a syndicated columnist. His email address is: letters@charleskrauthammer.com.