Warmbier's parents are blaming the Obama administration and North Korea, but the truth is that he was a fool to visit a country which teaches its children that Americans are baby killers. I would imagine that every American is closely watched in the hope that they will commit some minor infraction leading to their imprisonment. The only surprisingly thing is that Warmbier was not traded for favors, but then again, it appears that his life practically ended shortly after his imprisonment began.
The U.S policy of travel to totalitarian countries is schizophrenic. Travel to North Korea is far riskier than travel to Cuba, yet the State Department's webpage for the latter states that "Tourist travel to Cuba remains prohibited," though, of course, the Obama administration allowed Beyonce and Jay Z to visit. The Cuban-American lobby, especially politicians such as Marco Rubio, is largely responsible for this policy. The comparable State Department webpage for North Korea includes no such restriction, though another webpage "strongly warns U.S. citizens not to travel to North Korea." The U.S. should criminalize travel to the DPRK by Americans to prevent further tragedies.