On the night U.C. Berkeley burned, protesters chanted, "No borders, no nations, f--k deportations!"

That is not an immigration policy.

Lost in the outrage against President Trump (not to mention the alt-right provocateurs cashing in on his election) and the furor over his hastily executed travel ban is the fact that many of his opponents have embraced a position on immigration that is just as extreme in the opposite direction.

Make no mistake: The left's anti-borders, anti-nation protesters are radicals. But last year, mainstream Democratic presidential candidates spoke as if deportations should only be used as a tool for removing undocumented immigrants who commit serious crimes — not for simply enforcing America's existing immigration laws.

Bernie Sanders faced a backlash from the left when he criticized some guest-worker programs for suppressing wages and indicated he did not believe in open borders. (It apparently takes a socialist now to teach people that the law of supply and demand applies to labor too.) Sanders had to do damage control on this issue during the primaries.

Meanwhile, leaked paid speech transcripts showed Hillary Clinton saying she believed in hemispheric open borders, at least as an abstract goal. Both Clinton and Sanders not only promised to never deport children, but sometimes implied they wouldn't deport illegal immigrants who have children.

The last major bipartisan comprehensive immigration reform legislation, popularly known as the (failed) Gang of Eight bill, would have significantly increased overall immigration levels. "The legislation would loosen or eliminate annual limits on various categories of permanent and temporary immigration," stated a Congressional Budget Office assessment. "If… enacted, CBO estimates, the U.S. population would be larger by about 10 million people in 2023 and by about 16 million people in 2033 than projected under current law."

Those numbers are astonishing.

And remember, the last Gallup poll on the subject found that barely one in five Americans want to increase immigration. Never in more than 50 years of polling on this question has Gallup found more than 27 percent in favor of higher immigration levels.

Trump's executive order on immigration was too broad, obviously. It should have never even temporarily ensnared green card holders. Translators and others who have fought alongside our soldiers should have been better cared for, as well as people displaced by our wars. A clearer process should have existed for hardship exemptions. But that doesn't mean everything about the order was fundamentally wrong.

Of course, Trump has exacerbated his own problems with his loose talk about Muslims and other groups. But in response, many of Trump's critics are advocating immigration and refugee policies that are expansive even compared to what past liberal Democratic presidents have overseen and have no obvious limiting principle.

Fox News' Tucker Carlson (for whom I once worked) asked the head of an organization that accepts money from the federal government to help settle refugees how the United States should determine which of the 60 million refugees worldwide it will accept and what upward limit is consistent with our values. He didn't get an answer. That's illustrative of the way much of the left thinks of this issue. They want to let everyone in, out of a vague sense of goodness and a loose interpretation of the words emblazoned on the Statue of Liberty. But in practice, they have no idea how to balance feel-good goals with actual reality.

Billions of people live in countries that not only have lower per capita GDPs than the United States, but lower per capita GDPs than Mexico. In principle, is there any limit to the number who may immigrate here? Must that number always go up every year, never down? Do we not have a greater obligation to suffering working-class citizens in our own country, many of them people of color?

There also appears to be a growing presumption that the principle of non-discrimination on the basis of race, religion, and national origin — which is vital for governing a pluralistic society — must also extend to our immigration policy, even if it means admitting large numbers of people from countries that reject this kind of pluralism. There are lots of individuals all over the world who subscribe to values most Americans would consider illiberal. If they lived here, that would be their right. But do we have a duty to allow them to come as immigrants?

One need not paint the world's 1.6 billion Muslims with a broad brush or indulge in exaggerated fears common in some quarters of the right about sharia underneath the bed to realize that some of those concerns apply to Muslim-majority countries, whose migrants to Western Europe have in some cases proved resistant to assimilation. That non-assimilation has created worrying national-security problems.

Trump's election has reminded us how fragile the political norms and shared sense of belonging that sustain a nation can be. The United States has greater capacity than any country in the world to accept a diverse pool of newcomers. But that capacity is not limitless.

We must not allow the president's rushes to judgment to send us rushing in the opposite direction without thinking. A protest placard is not an immigration policy.