If Microsoft, as one plaintiff so tritely put it, is an “800-pound gorilla” stomping on competition and innovation, the Justice Department now has to prove it isn’t just a rapacious big-game hunter intent on killing something, anything.

And the attorneys general of the 20 states and the District of Columbia who joined in the anti-trust lawsuit against the software giant Monday? You know those thick clouds of blood-sucking insects that make the jungle so inhospitable?

The serious charge against Microsoft is that it attempted to conspire with Netscape to divvy up the Internet browser market. That’s collusion and that’s illegal, but Justice will have to do better than a few blustering inter-office memos. It will have a tough time making its case unless Bill Gates was stupid enough to put the conspiracy in writing.

Mr. Gates, while perhaps a bit arrogant, is not stupid. He proved that more than a decade ago when he recognized what IBM and Apple did not — that the big money in computers was not in hardware but in software. He proved that so successfully that his Windows software runs more than 90 percent of the world’s hardware.

To the computer user, that’s good. That means the machine at the office looks and works pretty much the same as the machine at home and the laptop on the road. Booting up is not a never-ending learning experience.

To Justice, that’s a problem. Its solution to this egregious example of uniformity and efficiency is to let every computer maker offer a different opening screen. It matters not to Justice that computer makers already do that, giving the consumers out-of-the box appearances that range from grazing cows to spinning planets to rotating whatsits. It matters not that most consumers rid their machines of such distracting nonsense at the earliest opportunity. Besides, if anyone at Justice had a tinkering teen-ager, he or she would know that customizing the opening screen is child’s play.

Justice’s other major remedy is even worse: Compel Microsoft to include Netscape’s browser with every copy of Windows `98. Never mind that just about every Internet service provider (you need to sign up with one to go on-line) provides Netscape with every subscription. And why should only Netscape get a piece of the action? What about Bob’s Storm Door and Internet Browser Co.?

It’s one thing to allege that Microsoft stifles competition and innovation, that it drives prices up and limits choices. With computers and software getting cheaper, faster and better almost daily, making the allegation stick will be a different story. For every stifled competitor Justice can come up with, Gates probably can counter with 100 innovators who went from impoverished code-writers to fabulously wealthy yacht-owners overnight thanks to a Microsoft buyout.

Besides, Microsoft’s dominance in applications is limited to home-use productivity, reference and entertainment programs, a relatively stagnant part of the industry. The real growth is in task-specific business applications, where Microsoft is hardly a player.

But the real grudge against Microsoft isn’t over applications. It’s not about Works, Encarta, Alien Bloodbath or even Internet Explorer. It’s over that operating system, Windows. The conventional wisdom, at least among those who’ve never tried writing an operating system, is that Windows would be a lot better if Microsoft weren’t constantly buying up better ideas and burying its tiny upstart competitors. Like that little mom-and-pop outfit IBM — its OS/2 was supposed to turn Windows into a dinosaur. OS/2 can be found in the bargain bin at your local software shop.

Filing a lawsuit is easy. The hard part is proving damage and the states will have a particularly difficult time, given that cheaper-faster-better factor. Armchair business strategists and second-guessing technophiles abound — truly injured parties will be a rarer breed. Microsoft is not Big Tobacco.

But of course the states’ involvement is not about damage or injury, it’s about money. Maine is not a party to the initial lawsuit, but there are rumblings that the Attorney General’s Office will join the swarm buzzing around Mr. Gates’ fortune. It’s probably inevitable. It’s the law of the jungle.