The Trump Administration is claiming that family separation is a continuation of Obama-era policy. This is false. Neither Bush Jr. nor Obama had policy with the effect of widespread family separation like Trump. Yes, the Obama administration detained families of undocumented individuals, but at least the families were kept together. There is not a Federal law stipulating or mandating that children be separated at the border. Family separation is a new policy under the Trump administration.
It doesn't surprise me that this is so heavily protested. Children are being kept in cages, and some parents are being deported without their children. It is interesting how the cliché "think of the children" has been used on the Right against same-sex adoption or transgender individuals entering the bathroom that best fits their gender expression, although neither claim has a basis in reality.
Study after study shows that separating children from their primary care-giver causes major adverse effects on their mental and physical well-being, including developmental delays, trouble sleeping and eating, and anxiety. This is all the more so the case when separating children from their parents at the border, much like we see now (MacKenzie et al., 2017). It's no wonder that American College of Physicians, American Psychiatric Association, and American Academy of Pediatrics are all against separating children from their parents at the border. This letter from the Physicians for Human Rights also cites literature on the effects. Former director of Immigration and Customs Enforcement (ICE) John Sandweg warns that this policy could create thousands of orphans. These findings and outcry from pertinent professionals on the effects this has on children only serves to support the moral outcry (see my Jewish religious argument on how to treat immigrants here).
The increase in these border crossings is caused by high murder rates and gang violence in Central America (see Clemens, 2017). These families crossing the border and risking harm, deportation, or death are doing so because they are fleeing from something horrible, something those of us in more developed countries could not begin to imagine.
What worries me is that Trump's stance on family separation is a continuation of his anti-immigrant policy (see tweet above). Trump lambasted the MS-13 for acting like animals. Yes, such gang activity is morally reprehensible. But it's also morally problematic to refer to human beings fleeing from inhumane conditions as "infesting our country," as if they are akin to a rodent or cockroach problem. Here are some fun facts about undocumented immigrants to better contextualize: they are less likely to commit crimes, they are not causing a fiscal drain, and they pay taxes. In this case, many of those crossing the border are asylum seekers. More to the point, the refugees and asylum seekers, such as the ones that Trump is attempting to deter with family separation, are such a non-threat that you are about 21,000 times more likely to get struck by lightning than get killed by a refugee!
You could argue that the problem is with illegal immigration only. If you think that Trump's problems with immigration are limited to illegal immigration, you would be wrong. In his first term as President, Trump has already taken issue with multiple forms of legal immigration, whether it is chain migration, Temporary Protected Status, DACA, low-skilled immigrants, or H1-B visas.
Even if you argue that they are breaking the law (91 percent were charged with misdemeanors, which further illustrates how disproportionate Trump's response is), it does not justify putting these people through such trauma. Family separation adds to the problems of an already-problematic immigration system in the United States. The red tape and wait for green cards and visas is so ridiculously long that telling asylum seekers to go through the system legally borders on farcical. Family separation adds to the problems of an already-problematic immigration system in the United States, a list of problems that Trump erroneously thinks could be solved with a border wall and more border patrol agents. Family separation is both a humanitarian calamity and another example of how Trump does not understand the cost that anti-immigration imposes. If any conservative truly cares about the children or family values, they will call on the Trump administration to stop with the family separation.