While the United States has witnessed several tragic massacres in his relatively youthful history, it seems that these man-made catastrophes have not been politically-motivated – at least in recent years.

The unspeakable bloodshed that occurred in Oslo, Norway on Friday was apparently promoted by the gunman’s hatred of Islamic immigrants. He sought to punish the country’s Labour Party, whom he blamed for allowing mass immigration into the country.

Could such a calamity happen in the United States?

Given the toxic brew of rising anti-immigrant sentiment and a highly-armed population (as well as a society replete with violent crime), it would seem such a nightmarish scenario would be possible.

But it hasn’t happened -- at least yet.

Earlier this year in Arizona, a young gunman named Jared lee Loughner tried to assassinate Congresswoman Gabrielle Giffords outside a supermarket in Tucson, Ariz. She survived the attack, although six other people died. Although Arizona has become symbolic of the nation’s growing unease with Hispanic immigration (the state passed a controversial immigration law last year), it’s not clear yet what Loughner’s motivation for the shooting spree was.

In November 2009, a Muslim major in the U.S. army, Malik Nadal Hassan, killed twelve soldiers and one civilian and wounded 30 at Fort Hood in Texas. Reports indicated that Hassan didn’t want to be sent to fight in Iraq – while this might be considered a politically-motivated mass murder, it hardly had anything to do with immigration.

Over four years ago, the country was shocked by the mass murder on the peaceful campus of Virginia Tech in Blacksburg, Va. An Asian-American student named Seung-Hui Cho killed almost three dozen people before killing himself. Cho had many personal demons and perhaps sought to emulate the Columbine school massacre from 1999, but, once again, this apparently had no explicit political motivation, nor with anything to do with immigration.

The infamous Columbine massacre of 1999 saw the killings of fifteen people by students Eric Harris and Dylan Klebold – again, this was a horror perpetrated by two mentally disturbed teenagers with some vague grievances against their school and classmates – but with nothing remotely related to immigration.

Perhaps the closest parallel with the Oslo killings would be the 1995 bombings in Oklahoma City which killed upwards of 170 people. Timothy McVeigh was part of a shadowy right-wing group of anti-government agitators. While immigration was likely one of their grievances against the state, there didn't appear to be an explicit connection between immigration and the deaths of all those people at the Murrah Federal Building.

The Norway massacre -- allegedly engineered by only one man -- was a highly-organized, well-prepared assault with an almost military precision. Yet the U.S. has many extreme right-wing groups which espouse violent rhetoric against both illegal immigration and the federal and state government which they blame for failing the people.

The parallels are eerie -- and yet nothing like the home-grown terror attacks of Oslo have occurred in the United States in recent memory. Also, keep in mind that the US is a country of 300-million people with a long history of armed civilians; while Norway is a peaceful land of only 5-million. Thus, it boggles the mind that such a tragic event could occur in Norway, rather than the U.S.