In striking at Libyan leader Muammar Qaddafi, President Reagan has by all accounts thrown a quick, effective military punch. So far, the Libyan operation has been the sort of armed engagement that public opinion in the United States tends to support.
But analysts question whether the US could have gone beyond this week's relatively limited military operations -- the ``small bites,'' in the words of defense expert Edward C. Luttwak of the Georgetown Center for Strategic and International Studies -- to deliver a knockout blow against Colonel Qaddafi.
``The state of American opinion allows only small bites,'' Dr. Luttwak says. ``The Grenada situation can be totally dealt with in one small bite. The Libyan situation cannot be. So we end up wounding Libya. It's like wounding a wild beast; you don't prevent him from doing a lot of harm.''
The use of military power has always been problematical in a democracy. As Secretary of Defense Caspar W. Weinberger has said -- and as military officers say they learned from Vietnam -- wars cannot be fought without public support.
To win such support, say public-opinion analysts, US military operations must meet three standards:
They must be limited and focused. In responding to six Libyan surface-to-air missiles launched against US warplanes over the Gulf of Sidra, officials say, the US was specifically defending its right to operate in international waters.
There has to be a clearly defined enemy. ``We know Libya is no friend of the US,'' says a public-opinion analyst. ``Since Libya is in a class with Cuba and Iran, it automatically bears the onus of events.''
The operations need to be quick and free of extensive casualties. ``One thing Reagan has learned: Get in and get out. Don't get sucked into a black hole of prolonged military involvement,'' says Richard C. Scammon, a Washington political analyst.
``The most important factor is whether the objective can be achieved in quick, decisive action,'' says Barry M. Blechman, a private defense analyst.
``In a democracy, the most difficult thing is the use of military power involving risk or loss of life in a situation that appears to be indeterminate, like Vietnam,'' Mr. Blechman says.
But if this week's defense of US navigation rights in the Mediterranean has satisfied the prerequisites for public approval -- an ABC News poll shows two-thirds of Americans support the US military action in the Gulf of Sidra -- analysts say the action has fallen short of the larger US objective of getting at the roots of Libyan-sponsored terrorism.
Moreover, public backing for limited military means has not translated into support for the use of force by proxy against Nicaragua's Sandinista government.
Two-thirds of the American people oppose new aid to Nicaraguan resistance forces, called ``contras,'' according to a recently released ABC/Washington Post survey. Whereas the Libyan action was speedy and ``sanitary,'' as one defense expert describes it, Americans fear that new contra aid could be a step toward direct US involvement in another protracted jungle war.
Finally, analysts say this week's action in Libya has left unresolved a longstanding disagreement within the Reagan administration itself on the appropriate use of military power as an instrument of American foreign policy.
In what many see as an ironic reversal of roles, Mr. Weinberger has been the leading advocate of restraint, warning of the need for extreme prudence in utilizing America's vast military might.
Secretary of State George P. Shultz, on the other hand, sees danger in such hesitancy, warning that imposing limits on the President's freedom of action may be inviting more serious trouble later.
By risking military confrontation to back US rights in the Gulf of Sidra, the Reagan administration may have struck a blow for the Shultz point of view, some analysts say.
``There's an intangible aspect of Reagan's strike on Libya,'' says Joseph Fromm, director of the Washington office of the London-based International Institute for Strategic Studies. ``It sends a message that Reagan is prepared to say that power has utility and that he has the stomach to use it.''
But despite the increased assertiveness of recent Reagan policy in Libya, Central America, and elsewhere, analysts say Reagan, like other presidents before him, may remain captive to ambivalent public attitudes that make the use of force permissible only in limited circumstances.
Fears of engagement in Central America override the US public's concern over the threat communism poses to US strategic interests in the region. While Americans agree the threat exists, a sizable majority disagrees with the means to combat it.
To the extent the President has seemed to favor a military response to the danger, approval ratings for his management of foreign policy in the region have suffered.
And even as regards Libya, Americans support the President's means for dealing with Qaddafi but question the long-term consequences.
A whopping 83 percent say they're ``glad that the USA is standing up for rights around the world even if it means taking some military risks,'' according to a USA Today poll. But that outpouring of support is nearly matched by fears that the incident may increase the chances of war in the region and lead to new outbreaks of terrorism directed at Americans around the world.
When strategic needs are at odds with what is politically allowable at home, analysts conclude, US policymakers are often forced to choose between unacceptable options.
``We have only two options,'' says Edward Luttwak. ``We can accept Qaddafi and let him do what he wants, or we can destroy him. Anything in between is no good option.''
But faced with hard political realities, says Luttwak, policymakers can learn to make do.
``Qaddafi may be an irritation, but he's not sufficiently important to change the political consensus in the United States,'' Luttwak says.