You’ve seen this gag in a hundred old cartoons:

Cat turns to flee angry dog, steps on a rake instead, knocks himself silly. It’s not sophisticated humor, but it is a visceral illustration of an abiding truth: Panic can make you hurt yourself.

Some of us, I think, need reminding. Consider the case of Rachael Ray and the scarf that made people scream.

Ray, of course, is the preternaturally perky host of cooking shows on the Food Network – and a spokeswoman for Dunkin’ Donuts.

In that capacity, she wore the aforementioned scarf around her neck in an online ad – and people started screaming. It seems that in the eyes of conservative columnist Michelle Malkin and a handful of blogosphere blowhards, the scarf resembled a kaffiyeh, the Arab headdress most infamously worn by the late PLO leader Yasser Arafat.

Me, I thought the paisley scarf resembled a paisley scarf, but then, I haven’t been taking my paranoid lunatic pills lately, so what do I know? Those with more discerning vision cried foul and late last month, the doughnut maker crumbled, pulling the ad lest anyone assume the company was selling mass terror along with its iced coffees and crullers.

As it happens, at roughly the same time the Guardian newspaper in London was reporting the case of one Rizwaan Sabir, a 22-year-old student working on his master’s at Nottingham University. Sabir was arrested, held for six days, and subjected to what he describes as psychological torture after he downloaded a copy of an al-Qaida training manual.

Also arrested: a university administrator, Hicham Yezza, on whose computer the manual was stored. It seems Sabir had asked Yezza to print the 1,500 page document because he could not afford to.

But neither man will be prosecuted for terrorism. According to university officials, the materials Sabir downloaded were directly related to research for his degree. And get this: You know where Sabir says he got the offending manual? From a U.S. government Web site. In other words, it was publicly available and hardly top secret.

Taken together, these two episodes neatly illustrate what much of our world has become in the almost seven years since September 2001. On the one hand, silly, able to see terrorism hiding behind every bush and hen house. On the other hand, petrified, convinced that overreaction is the only reaction. So we look suspiciously at everyone whose name is not Smith, Johnson or Jones, inspect scarves for terroristic subtext, but glance the other way as torture is committed, intolerance is embraced, habeas corpus is ignored and freedoms of speech, dissent and privacy are abridged.

It’s like we have awakened into the 1950s. The paranoia is there, the gratuitous ruination of people’s lives is there, the abiding and unrelenting fear is there. The only thing missing is Joe McCarthy asking, “Are you now or have you ever been …?”

Apparently, Colin Powell was wrong. “We’re Americans,” he said after the Sept. 11 attacks, “we don’t walk around terrified.”

But we do. And because we do, we injure ourselves as surely as a cartoon cat panicked by a cartoon dog. So that here we sit, banged up something fierce: the rule of law, broken; moral authority, blackened; freedoms, fractured; seriousness of purpose on life support.

All in pursuit of a chimera called security we have yet to capture and never will. So we might as well go back to being America. I mean, when the Zeitgeist is indistinguishable from a Warner Bros. cartoon, something is wrong.

To put it another way, let me repeat: Panic will make you hurt yourself. What’s it tell you that we have yet to learn something Bugs Bunny figured out a long time ago?