Actually/Trump did open concentration camps

Myth: Trump did not open concentration camps.

Myth

In response to a 2019-06-18 Tweet by US Representative Alexandria Ocasio-Cortez (aka "AOC") which stated that "This administration has established concentration camps on the southern border of the United States for immigrants, where they are being brutalized with dehumanizing conditions and dying.", Republicans repeatedly claimed that the claim of "concentration camps" was inaccurate and historically ignorant:

• "Please @AOC do us all a favor and spend just a few minutes learning some actual history. 6 million Jews were exterminated in the Holocaust. You demean their memory and disgrace yourself with comments like this." - Liz Cheney
• "I think Congresswoman AOC needs to apologize [...] Not only to the nation but to the world. She does not understand history. [...] She does not understand what is going on at the border at the same time. But there is no comparison...and to actually say that is embarrassing. [...] To take somewhere in history where millions of Jews died...and equate that to somewhere that's happening on the border...she owes this nation an apology." Kevin McCarthy (R-Calif.)

Reality

• "We have what I would call a concentration camp system,” Pitzer says, “and the definition of that in my book is, mass detention of civilians without trial." – Andrea Pitzer, historian specializing in concentration camps
• "I know what concentration camps are. I was inside two of them, in America. And yes, we are operating such camps again." – George Takei, concentration camp survivor

The Republican logic, to the extent that logic plays a role, seems to rest on conflation of concentration camps with death camps (sometimes euphemistically referred to as "extermination camps"). Concentration camps were not always death camps. The definition of concentration camp is, in part, "a place where large numbers of people (such as prisoners of war, political prisoners, refugees, or the members of an ethnic or religious minority) are detained or confined under armed guard" or "a guarded compound for the detention or imprisonment of aliens, members of ethnic minorities, political opponents, etc.". The US's ICE detention camps opened in 2019 and the WWII Japanese internment camps fit both of these definitions.

The comparison to German concentration camps in WWII is especially apt, as Hitler's creation of those camps was apparently inspired by US treatment of Native Americans.

Also, at least one camp was, for a time, being run by a neo-Nazi.

Further Reading

• 2019-07-06 Japanese internment camp survivors protest Ft. Sill migrant detention center
• 2019-06-19 Powerful Thread Explains Why Alexandria Ocasio-Cortez Calling The Migrant Detention Centers 'Concentration Camps' Is Actually Quite Accurate: tweeted by Charlotte Clymer, an Army veteran who worked at the US Holocaust Museum giving tours (via George Takei on Twitter)