Reactions to Donald Trump's immigration plan have been predictably polarized, with people either thinking it will make America great again or considering it an invitation to a pogrom. Taken seriously and stripped of excesses, though, it points the way toward a sensible compromise on immigration policy.

Taking it seriously isn't always easy, since Trump doesn't seem to take it all that seriously himself. The plan on his campaign website suggests he'd stanch the flow of immigrants coming to work at American technology companies; on Twitter, by contrast, Trump says that he wants talented foreigners to come work in Silicon Valley and become citizens.

The plan says nothing about how most unauthorized immigrants already in the U.S. would be treated. But Trump has suggested that he'll send them to their countries of origin and then let them come back, which seems like an expensive and administratively complex exercise in pointlessness (albeit one that other politicians have sometimes also suggested). So like most of the Republican presidential candidates and Hillary Clinton, he favors an eventual amnesty.

The best feature of the plan, to my eyes, is its promise of a "moderation" in total immigration levels. Americans who want to allow fewer legal immigrants into the country have consistently outnumbered those who want to allow more. But far more politicians have fallen in the latter camp - usually without debating it. A smaller inflow would make assimilation easier and could relieve the economic pressure on low-wage workers (including previous immigrants).

The worst feature of the plan is its promise to end "birthright citizenship," so that the children of illegal immigrants are no longer automatically considered U.S. citizens. I say that even though the U.S. is an outlier in following this practice, even though it complicates enforcement of immigration laws (since it means either breaking up families or sending away citizens), and even though there's a legitimate debate over whether the Constitution really requires it.

Ending birthright citizenship is neither necessary nor sufficient to reduce illegal immigration. Trump's other proposals - such as cracking down on visa overstays and expanding the E-Verify system - would probably be much more effective and much less politically damaging. And even if Congress passed and the president signed a bill ending birthright citizenship, the courts would almost certainly strike it down.

So forget the citizenship proposal and some other far- fetched portions of the plan. Two remaining ideas - a reduction in legal immigration and an eventual amnesty - could be a viable compromise between the contending sides of this debate. That compromise would reflect the reality that we're not going to deport the vast bulk of the illegal-immigrant population and that the U.S. economy doesn't need to continue taking in as many unskilled immigrants as it now does.

One thing that shouldn't be part of a compromise is Trump's call to boost enforcement of current law. That should instead be a prerequisite to compromise, indeed a prerequisite to having any serious immigration policy. Polls have often shown that Americans are open to an amnesty. But they don't trust that the laws are going to be enforced in the future, or that any amnesty would be the last one.

That's one reason there's a market for Trump to promise tough enforcement, even in outlandish ways. For all his flaws, he understands that the public doesn't trust lawmakers on this issue.

In 1952, the conservative intellectual Irving Kristol wrote an essay about why so many Americans were attracted to the anticommunist demagogue Joseph McCarthy. To adapt what he said then: One thing Americans know about Trump is that he is unequivocally for getting control of immigration. About the rest of our political leadership they feel they know no such thing. And with some justification.