The similarities and differences of the Tucson shooting and the Virginia Tech mass murder are instructive, so it's a little surprising that the MSM has not been more interested in exploring comparisons. In both cases, the schools faced a disruptive student who was potentially violent, but different steps were taken.

At Virginia Tech, authorities shrank back in political correctness from expelling Korean immigrant Seung-Hui Cho (pictured) even though he had stalked women students and exhibited other violent tendencies. It's doubtful the university would have acted so generously toward a white American who behaved in such a menacing way, because there's no gaggle of law firms and ethnic protection groups for US citizens as there is for immigrants and illegal aliens.

The result of Virginia Tech's lack of responsibility: the worst mass shooting in US history, with 32 killed and more than two dozen wounded, most of whom were students.

(Incidentally, if the six people murdered in Tucson were University of Arizona students and not mostly adult Americans, I doubt that the"memorial" service on the UA campus would have devolved into a noisy pep rally for Obama. The memorial for Virginia Tech victims was properly respectful because many students knew someone who had been murdered.)

Pima Community College may have learned something about self-protection from the Virginia Tech experience, where a lawsuit against the university is going forward. Most of the families accepted the $11 million state settlement, but the relatives of Julia Pryde and Erin Peterson did not, because they wanted the university's negligence to be better revealed.

So Pima College authorities paid attention to the five altercations Jared Loughner had with campus police and placed him on suspension.

Jared Loughner Had 5 Run-ins with College Police, CBS News, January 10, 2011

On Oct.4, Loughner and his parents met with college administrators and withdrew from school. On Oct. 7, Pima sent a letter to Loughner telling him that if he intended to return to school, he would have to get a letter from a mental health official indicating 'his presence at the College does not present a danger to himself or others."

When a student appears so dangerous that classmates fear for their lives and sit near the door, it is wise for the college administration to bar his presence in the school. However, that precautionary measure is not enough. The college has likely protected itself from lawsuits but did not fulfilled its civic responsibility to inform the local community of a dangerous person.

The average age for the onset of schizophrenia in males is 18, so it makes sense for high schools and colleges to become more aware that disturbing changes in students' behavior may indicate serious mental illness. There needs to be a better link between educational institutions, mental health practitioners and the police. Insane people are prohibited from buying firearms, but their names must appear on the NICS database.

Today fewer of the mentally ill are institutionalized and they are harder to identify for that reason. But anyone deemed too insanely dangerous to attend college is also too hazardous to purchase weapons.

The best way to protect Second Amendment rights is to keep insane persons and illegal aliens from buying guns.