Anti-immigrant protests are back. And they’re targeting detainee families.

As thousands of families have fled Central America for the US, the federal government has struggled with what to do after apprehending them. While it prepares detention centers, it’s keeping migrant families in Border Patrol facilities in other parts of the country. And in some cases, neighboring, anti-immigration residents have protested.

Today, a protest actually got dangerous. 140 immigrants from Texas were sent to Murrieta, CA — a suburb about halfway between Los Angeles and San Diego — to be processed in the federal Border Patrol station there. In response, anti-immigrant protesters blocked the road to the facility — causing the buses to turn around and go to another Border Patrol station instead. Cops had to intervene to keep protesters from following.

This is some extremely ugly behavior: protesters are yelling “Go home!” at a bus full of children, and physically preventing detainees from going to the place they’re supposed to go and forcing the government to send them somewhere else.Frankly, it’s a kind of personal, in-your-face nativism that wasn’t actually seen during the most recent debate over immigration reform in Congress. And it’s not that these residents are misinformed about who was coming on those buses: at a town hall last night, the mayor told residents, “What we’ve been told is that most of these immigrants are families. These are mothers and young children, or fathers and young children.” That didn’t mollify residents last night, and it didn’t stop protesters from coming out today.

But the sad irony is that what they’re protesting is a robust immigration enforcement system. A secure border doesn’t mean that there’s a force field around the country, and that no one can physically cross without papers — it means that people who cross without papers are generally caught by enforcement agents. And that’s exactly what happened to these families. Once they were caught, instead of getting a court date and being released into the interior, Border Patrol sent them to be processed at a second facility — making sure they remain in government custody for as long as possible. Most of them will probably be detained: a document handed out by Immigration and Customs Enforcement officials says that some families “may” be temporarily released after processing, but those will likely be fitted with ankle bracelets. And most of them will probably, ultimately, be deported.

But it’s impossible to satisfy people that the government is being tough enough with immigration enforcement when they don’t trust anything the government is saying about it. And that’s what is happening in Murrieta.

Residents last night expressed fears about “what the plan is in the event that these people are starting to be dumped all over town,” even though the mayor assured them that no one would be released in Murrieta. One local summed it up: “I’m sorry, I don’t feel that our officials — and I apologize to everybody — are being really honest.”

This is an unbreakable cycle. If someone’s inclined to believe that the government is letting unauthorized immigrants run rampant through the US, anything the government says to the contrary will make her trust them less.

And that’s why, politically speaking, there’s no such thing as deporting one’s way to a win on the issue of immigration. The White House saw this back during the administration’s first term, when setting deportation records every year wasn’t enough to gain the trust of immigration hawks. Now, as children and families continue to flee violence by trying to find a better home in the US, those who feel invaded or overrun by unauthorized immigrants are feeling vindicated. And anyone who feels threatened enough to block the road and shout “Go home!” at a bus full of captive mothers and children is unlikely to feel, ever, that the government has immigration enforcement under control.