Congress seems very shock-prone these days. Only a few weeks ago House Democrats were shocked to find Nicaragua's President Daniel Ortega in Moscow. He had flown there only hours after the House blocked President Reagan from giving any aid to Nicaragua's anti-Sandinista guerrillas. Sen. James Sasser (D-Tenn.) confessed that had he known about the Ortega trip, he would have changed his vote and supported the contras. (Why is it that Democrats cannot figure out where a Marxist-Leninist -- which Ortega has declared himself to be -- is headed, until presented with his travel schedule?) Other liberals, who on the floor of the House had just challenged Reagan's characterization of Nicaragua as a Soviet base, declared themselves variously upset, embarrassed, even betrayed by Ortega's unsportsmanlike conduct.

This week, more unsportsmanlike conduct, another round of indignation. It seems that not only our enemies disappoint us. Some of our associates around the world are bad actors too. One group, trained in Beirut by the CIA as a counterterrorist force, hired its own free-lance terrorists, who tried to kill yet another terrorist with a car bomb. It killed 80 bystanders instead.

Terror is terror, and the bombing was both a crime and tragedy. Yet when the event happened months ago, before it acquired a third-hand connection with the United States, it was accorded a few 30-second bites on the evening news, and then dismissed as more of the Lebanese same.

The fuss now is not about the act, which was barely noticed, but about the American connection. What exactly is the charge? The reports indicate that the CIA neither authorized nor knew about the bombing and, when it found out, cancelled the whole Beirut operation. The CIA can be criticized for the way it carried out this mission, and for its lousy choice of participants (though the netherworld of Beirut terror is hardly a recruiter's dream). But beyond general indignation, what exactly is it that so upsets critics about the original counterterror idea?

Everyone is against terrorism. Everyone wants to do something about it. And everyone, even the biggest dove, is in favor of gathering intelligence. Now, what to do with that intelligence? If you find out certain groups are trying to kill Americans -- and in Beirut they most certainly are -- you can use the intelligence to avoid attack and run. This response is as futile as it is dangerous. Lebanon's terrorists are people of proven seriousness. They will try again tomorrow.

If the United States does not want to let itself be driven from the Middle East -- and we are talking here about maintaining embassies, not Marines -- and if it wants to protect American nationals and diplomats, it must be prepared to act on, not just gather, information.

What kind of action? Overt action is of proven uselessness. Battleships and bombers either kill Lebanese indiscriminately or they risk producing American prisoners. (Remember Lt. Goodman?)

That leaves covert action, not a terribly popular item these days on Capitol Hill. Yet, covert action to overthrow governments is one thing. The purpose of this operation was quite different. It was meant to defend American lives against terrorists. And, of all the rationales for the use of force abroad, that narrow purpose is perhaps the most widely accepted and easily justified. Many who opposed the Grenada invasion, for example, said they would have supported it had they thought it was really meant to rescue American medical students.

Who is to carry out such covert action? Much of the indignation on Capitol Hill has been directed at the use of proxies or, as Rep. Pat Schroeder (D- Colo.) calls them, "loose foreign proxies." The problem with using foreigners is that they are harder to control than Americans. True. But using Americans is highly dangerous and risky. It is not easy to keep a group of American commandos hanging casually around Beirut or to ferry them inconspicuously from the Sixth Fleet.

And besides, how do you penetrate the world of Lebanese terror without loose foreign proxies? I, too, would be happier if we could infiltrate the Shiite Party of God with a Yalie, PhD in international law, MA in ethics. But no matter how well cut his kaffiyeh, I doubt he would make it past the front door. The remaining alternative (to doing nothing) is to risk working with foreigners whose aims coincide with ours. That they may turn out not to be Blackford Oakes should hardly surprise us.

And yet we are surprised -- shocked -- every time friend or foe fails to measure up. I am not arguing against keeping our standards high -- only against our ridiculous fits of outrage when we discover, monthly, that not everyone lives up to them. It is exactly 40 years now since the United States became the preeminent power in the world and, as a consequence, charged with dealing with foreigners even to the murkiest corners of the earth. One might have thought that 40 years of Old World work would make a dent in some of our New World naivet,e. Give us another hundred.