Sen. Jeff Merkley speaks on Capitol Hill in Washington in 2013. (AP)

Sen. Jeff Merkley’s trip to the border with Mexico on Sunday didn’t go as planned. As our James Hohmann reported on Monday, Merkley (D-Ore.) had traveled to Texas to view a detention center housing children who had been separated from their families after crossing the border, a group that’s swelling in size following the implementation of a new Trump administration policy aimed at deterring future families from attempting to enter the United States. Merkley’s request to see the facility on Sunday evening was denied, and the private firm running it called the police to get him to leave.

But the authorities weren’t done with him yet. On Monday afternoon, the White House released a statement disparaging Merkley’s trip.

“Senator Merkley is irresponsibly spreading blatant lies about routine immigration enforcement while smearing hard-working, dedicated law enforcement officials at ICE and CBP,” the statement from deputy press secretary Hogan Gidley read. “No one is taking a public safety lecture from Sen. Merkley,” it added, “whose own policies endanger children, empower human smugglers and drug cartels, and allow violent criminal aliens to flood into American communities.”

Following that statement was a section identified as being “on background,” meaning that it was not intended to be attributed to the White House. Despite that, it was included in a report by CNS News. In that addendum, the White House tied Merkley to two violent crimes committed by immigrants.

“The victims of Sen. Merkley’s reckless open borders policies,” the section read, “include his own constituents: a 65 year-old Oregon woman who was sexually assaulted by an illegal alien that had been previously deported 20 times prior, and a young Oregon girl who was allegedly raped several times by a twice-deported illegal alien.”

The first reference is to Sergio Jose Martinez, arrested last July. The second refers to Anastacio Eugenio Lopez-Fabian, arrested this year.

Martinez’s history with federal immigration authorities is about as long as Merkley’s tenure in the Senate. Martinez was first deported in April 2009, according to a statement provided to The Washington Post by the Department of Homeland Security. Merkley joined the Senate that January.

“As is their custom, the White House is trying to change the subject by smearing Senator Merkley,” Merkley’s communications director, Ray Zaccaro, said in a statement. “It’s no surprise because there is no defense for their abhorrent policy of snatching children from their parents.” He added that the senator and his staff “saw children in cages yesterday at the DHS processing center. We still have no idea what’s happening in the detention center where reportedly up to a thousand children are being held, since they refused the senator’s request to go inside.”

Merkley’s team naturally wasn’t interested in getting into a debate over the Martinez and Lopez-Fabian cases. But it’s worth highlighting how the White House handled Merkley’s successful effort to draw attention to the family-separation policy: by implying that Merkley is coddling and encouraging violent criminal immigrants.

This is both a new and an old tactic for President Trump. His campaign was predicated, from the outset, on the idea that immigrants entering the country were criminals. Rapists and drug dealers by default, with an asterisk that some of them might be good people. But it’s only in recent months, with the president’s new embrace of MS-13 as a political foil, that he has really begun to use crimes committed by immigrants as a political tool against his opponents.

It’s important to note research indicating that immigrants commit crimes at lower rates than native-born Americans, that the violent-crime rate has fallen even as the number of immigrants has risen and that there’s no link between illegal immigration and violent crime.

Yet criminal members of MS-13 have become, for Trump, the quintessential immigrants crossing America’s southern border. On Long Island last month, he implied that young people who had come to the United States in a wave four years ago were not simply fleeing violence in their home countries.

“They look so innocent,” Trump said of that group of more than 100,000 migrants. “They’re not innocent.”

He proceeded to tell stories of horrible crimes committed by MS-13 gang members, clearly attempting to ascribe those specific crimes to the general population of immigrants who cross into the United States from the Mexican border. His recent insistence on calling members of MS-13 “animals” has had the side effect of goading Democrats into opposing the idea of referring to immigrant groups in dehumanizing language, which Trump and his allies quickly used as evidence that his political adversaries loved the criminal gang. (Literally. He called House Minority Leader Nancy Pelosi, a California Democrat, an “MS-13 lover.”)

The attempt to tie Merkley to two criminal immigrants is the same rhetorical move. Merkley’s trip to Texas was a criticism of Trump’s policy, a policy that exists and that exists at Trump’s order. (“By doing so with taxpayer dollars,” Zaccaro’s statement said, “they are making all Americans complicit in this unconscionable action.”) The White House’s response was to focus on two immigrants of more than 100,000 in Oregon who committed crimes entirely unrelated to Merkley or to the issue Merkley hoped to highlight — and, in one case, who had been on the government’s radar screen from Merkley’s first days as a senator. Even if Merkley had actively encouraged a policy specifically aimed at allowing Martinez to stay in the country and commit crimes, he’s one senator of 100 in a Congress of 535.

This is the game Trump is playing, though. Anything short of an iron fist in dealing with immigration and, it seems, you’re at least partly responsible for any criminal act committed by any immigrant. If you suggest that dehumanizing language is a worrisome rhetorical move, you’re identified as sympathetic to criminals who carve up young women with knives. If you question the administration’s policy of taking children as young as 18 months away from parents as families flee violence in Central America, you’re going to be held to account for two other people who broke the law.

In any population there are criminal actors. There are fewer in the population of first-generation immigrants than in the population of citizens born in America. The Trump administration is lifting up the worst examples of immigrants to argue that no quarter should be given to the immigrant population overall — specifically to support his strongman approach to the issue.

Merkley made his trip to the border to highlight the administration’s policy of family separation. He inadvertently also drew attention to how far the White House will go to defend it.