Terrorists are sneaking back into our living rooms again, not through the window but via the television screen. How should we greet them? In the 1970s, hardly a week seemed to pass without a hostage-taking drama gripping the Western world. The ''theater of fear,'' as Rand's terrorism specialist Brian Jenkins terms it, was all too frequently in session.
We, the audience, watched rivetted as Carlos (Venezuelan terrorist Ilich Ramirez Sanchez) operated his Palestinian-European-Latin American network out of Paris, as hijacked airliners sought Mideast landing grounds, as the tragedy of Munich was followed by the Israeli hostage-rescue raid into Entebbe, Uganda.
Today, the ''theater'' is still there. But after several years of declining public attention, the actors and directors are changing. And so are the plots they hatch.
One has to be wary of statistics on international terrorism. Different experts use different definitions. It is not easy to draw into the same chart the ''apples'' of unfulfilled threats and the ''oranges'' of huge car-bomb explosions. But there are some discernible trends.
After rising through much of the 1970s, the number of international terrorist incidents recorded by United States officials has leveled off since 1978. True, they remain on a high plateau. The proportion of them involving Americans continues to rise. The number of known terrorist groups has doubled in a decade. The number of people being killed also has soared.
But some of the more foreboding forecasts of the '70s - particularly the expected escalation toward use of high-tech, nuclear, chemical, or biological weapons - have not been fulfilled. Attention-grabbing barricade and hostage incidents, such as embassy seizures, have notably declined.
According to Mr. Jenkins, these latter attacks have dropped from 20 in 1980, to 10 in 1981, to 5 in 1982, and only 1 last year. Better security, hardened government resistance to blackmail, deployment of highly trained anti-terrorist squads (such as the British SAS commandos who regained control of Iran's London embassy in 1980) have had their effect.
All this has produced a paradox: While the number of people being killed by terrorists has continued to increase, we, the public, have tended to tune out - at least until shaken up again by the sheer size and destructiveness of last year's car- and truck-bomb attacks.
Which brings us to the new actors and directors coming to the fore. If the early 1980s have a terrorist trademark, it is the apparently state-sponsored terrorist, often a fanatic Shiite Muslim, sometimes a suicide, who uses powerful and sophisticated bombs or an assassin's bullet to drive home his patron's bloody message.
International terrorism in the '80s has become in many instances a mode of low-level conflict between nations, a comparatively cheap and easy way of carrying out brute diplomacy against one's foes. Where a handful of nations in the '70s - from North Korea, the Soviet Union, and Cuba to Libya, South Yemen, and Iraq - are known to have subtly provided cash, passports, safe houses, and weapons for various terrorist groups, some of today's terrorism appears to be more directly state-sponsored, the connections more thinly veiled.
''A very important tendency,'' a State Department official remarks, is the use of murder and assassination by states. The fiery fundamentalism of Ayatollah Khomeini's Iran and the cold calculation of President Assad's Syria are much on the minds of those combating terrorism, but state sponsorship is not exclusively a Mideast phenomenon. It was North Koreans, for instance, who triggered the bomb that decimated the visiting South Korean Cabinet in Rangoon, Burma, last fall.
How should we react? In the words of Georgetown University's Robert Kupperman , ''How does a large government deal in proportionate terms with a comparatively small threat?''
With firmness - still better security and intelligence, improved cooperation between allies - and restraint. The restraint is easier if we remember that the terrorist, unable to muster armies, is forced to resort to the weapon of the weak: a drama of exaggerated fear, directed as much against us in our living rooms as against its victims, and specifically designed to produce an excessive response damaging to our own free institutions.