IF THE United States is marching toward war with Iraq, the U.S. military had better make sure it gets off on the right foot.

The opening blows in such a clash could be crucial; maybe not to the eventual outcome but to the level of American casualties and the degree to which the public and Congress will continue to support a fight if those casualty levels are very high at the outset.

The Iraqi forces are not Panamanian, or Grenadans, or Libyans. They can fight back. They have large stocks of by now well-dispersed Soviet-made missiles, Soviet and French-made fighter-bombers, long-range artillery, chemical weapons and huge tank armies that can take a heavy toll on American and allied troops if not neutralized very early in a battle.

There should be little doubt about the outcome. The Americans possess well-trained troops and awesome striking power and should be able to confront Iraq with a sustained level of punishment night and day from air, sea and land forces that goes far beyond anything that Saddam Hussein's military had to endure during their ultimately fruitless eight-year war with Iran.

What is disturbing, however, is that over the last 10 or so years, the American military has had some fumbles at the start of operations that could have been costly against a more potent enemy.

For example, the supertanker Bridgeton -- the first Kuwaiti vessel that sailed into the Persian Gulf in July, 1987, under a U.S. flag and escorted by three U.S. Navy warships -- hit a mine on that maiden voyage. The U.S. Navy, which had nine warships in the Gulf at the time, had no minesweepers among them although mines were known to be a threat. Of four Soviet navy ships in those waters at the time, three were minesweepers.

Much more disturbing was the aborted 1980 attempt to rescue American hostages in Tehran. The plan was bold, the commandos highly trained. But three of eight helicopters included in the mission experienced technical failures and a plan that represented the best of American audacity failed because of another American trait, excessive faith in technology.

Since the current U.S. build-up in the Persian Gulf began in August, 15 helicopters have crashed or been damaged in accidents. A mainstay of the Army's heliborne attack forces now in the Gulf, the new Apache gunship, is the target of a highly critical General Accounting Office assessment of its durability, although it has not been involved in any of the crashes thus far.

Post-invasion critiques of the October 1983 U.S. invasion of Grenada -- a tiny Caribbean island defended by a detachment of some 700 Cubans -- revealed serious flaws in communications and coordination between all four military services. As in the Iran hostage attempt, post-invasion critiques raised questions about the military's apparent need to involve all four services in all such undertakings. Grenada got underway without up-to-date intelligence and even local maps. It also showed, once again, the vulnerability of helicopters. Had the Cuban defenders been more numerous and more well-armed, U.S. losses could have been much higher and the operation viewed as much less successful.

That year, 1983, was not a good one for the U.S. military.

In October, a suicide bomber in Beirut killed 241 U.S. servicemen by driving a truck filled with explosives into a Marine barracks that had virtually all of its defenses down despite the tension in the city.

In December, 28 attack planes from U.S. aircraft carriers struck for the first time at Syrian gun positions in Lebanon in a very high-stakes raid. Though highly controversial because it involved American air attacks against Arabs, it was poorly planned and rushed on orders from civilian and military commanders who were not on the scene. Two U.S. warplanes were shot down, one pilot was killed and another taken captive in a raid against anti-aircraft defenses carried out in broad daylight and with some of the attack jets carrying far less than the proper load and type of bombs.

A few days later, the Navy's only battleship, the USS New Jersey, opened up its giant 16-inch guns for the first time against Syrian targets in the Lebanese mountains with a considerable degree of inaccuracy, the shells reportedly falling on mostly deserted hillside towns.

Two other more recent events in the Persian Gulf -- the allegedly accidental attack on the USS Stark in 1987 by an Iraqi jet firing French-made Exocet missiles that killed 37 sailors, and the shooting down of an Iranian jet passenger plane with 290 civilians aboard by the USS Vincennes in 1988 -- also provide grounds for concern about initial reactions to combat and the double-edged sword of high-tech weaponry.

In the case of the Stark, the captain was eventually reprimanded for lack of readiness and a failure to activate the many high-tech guns and electronic counter-measures these ships are equipped with. But while the Stark was too slow to fire, the Vincennes turned out to fire too quickly, undoubtedly worried about just what happened to the Stark skipper and crew.

Finally, a small but intriguing footnote to the invasion of Panama last year was the first use in combat of the new F117A Stealth fighter-bomber, the most advanced technology plane operational in the U.S. arsenal. One of the two jets used missed its bombing target by a wide margin. This may have been due more to confusion over last minute changes in which plane was to hit what target. But it still seems worthy of a list of warning signs about first use of high-tech weapons in battle.

All of these incidents are more complicated than the brief mention of them made here. There are some mitigating factors in every case. Yet most or all of these episodes have in fact been the subject of concern inside the military and in Congress. To avoid thinking about the collective meaning of them could be much more costly.

At issue is whether some kind of a thread connects them that runs through military planning and execution. Is there anything about how we have taken that first step in combat situations that should be a warning sign or an alarm bell?

By most accounts, the huge American build-up in the Persian Gulf since Iraq invaded Kuwait in August is different from these previous situations. The new Chairman of the Joint Chiefs of Staff, Army General Colin Powell, showed in Panama that he is not going to take any chances about going into battle unless he feels he has enough troops and fire power to keep the odds very much in his favor. Although the presence of allied forces in the region would seem to pose further complications, the American build-up is proceeding from a rather well-established and deliberate plan that U.S. military leaders have been developing ever since the Persian Gulf became a hot spot a decade ago.

Still, included in that build-up is an array of new weapons -- such as the Patriot air defense system, M1 tank and many sophisticated electronic warfare black boxes -- that have not been tested in combat. While President Bush has won strong support at home and abroad for his build-up as a way to pressure Iraq to get out of Kuwait, the public, Congressional and international coalition supporting actual fighting is undoubtedly much more fragile. In this particular military contest, if it comes to that, the early score may turn out to be more important than the final tally.

And, for whatever it is worth, there is this nagging history of initial missteps. Fortunately, those have not meant more than momentary setbacks. But Iraq presents a more formidable enemy than we have faced in a long time.

Michael Getler, The Washington Post's Assistant Managing Editor for Foreign News, covered military affairs for he paper for several years.