For one thing, he was adamantly opposed to the notion that an American charged with a crime in a foreign country should be extradited anywhere except the country where the alleged crime took place. The Ukrainian and/or German governments apparently had no interest in prosecuting him, so it seemed pretty bizarre to have him extradited somewhere else just because another government did. This is something worth thinking about for anyone who is familiar with the cockamamie ideas surrounding the International Criminal Court, war crimes tribunals for U.S. government officials, etc.
As I remember it, Buchanan's second point was that it was disgraceful for the U.S. government to deport Demjanjuk -- on the grounds that he had falsified his immigration documents to hide his past in the Ukraine -- in the first place. Buchanan correctly noted that the U.S. government basically deported him for being a retired auto worker instead of a rocket scientist . . . since this same U.S. government had gone to great lengths in the past to do the exact same thing for various German scientists in the post-WW2 era to whitewash their Nazi ties so they could immigrate to the United States.
I can't say I disagree with Buchanan on either point here.
So there are some illegal aliens Buchanan likes- nazis.
Actually his two main arguements were that Holocaust survivors were mentally ill, presumably only Jewish survivors, and that diesel fumes can't kill people, an absurd claim that got his column published in the Spotlight.
He's not an American citizen, he lied to get into the country, and on his citizenship application. The courts have held that consistantly. In no case other than ex-Nazis have I heard Pat opposed to enforcement of the immigration laws.