President Reagan has taken the first big step. He has lifted the three-year ban on all federal employment for the striking air traffic controllers.

The action is more symbolic and psychological than practical. Few of the fired controllers are interested in government service per se. They mostly don't have the skills for other well-paid work, and, even if they did, there's not that much work available in this period of federal budget and personnel cuts. What these men and women want is to be back in the towers, doing the one thing they are confident they do well, the thing that gave them a sense of pride and also a very nice income: directing airplanes.

The real significance of Reagan's action is that it signals an end to the punitive post-strike period during which the administration not only barred the illegal strikers from seeking other government work but also put roadblocks in the way of their unemployment benefits and called in their government loans.

That era is over, and that's good. But some of us still hope the administration will find a way to let most of the strikers return to their profession. I'm not talking about the sort of mushiness that has virtually taken the meaning out of no-strike clauses: the attitude, on the part of many government administrators and judges that says an illegal strike really isn't so bad as long as you promise not to do it again. That attitude is largely responsible for suckering the Professional Air Traffic Controllers Organization into its disastrous strike last summer.

What I'm recommending is an attitude that says you broke the law and you've been punished for it: by the irrecoverable loss of wages, by the destruction of your union and by the shattering of your lives. Now that you understand your folly, we have no further interest in vengeance.

That's what the government does with nations vanquished in law. That's what it does for convicted criminals whose crimes were motivated not by conscience but by greed. It's not unreasonable to try it with the illegal strikers.

I haven't heard from every controller on the East Coast since I first proposed that it was time to put the illegal strikers back to work. It only seems that way. Scores of controllers and ex- controllers have kept my phone lines busy for the better part of a week. If there is one consistent chord in their calls, it is sounded by the Washington center controller who said:

"We all know people we would like to have back in the tower with us-- friends, long-term colleagues, competent controllers who made a bad mistake. We need them, and we'd like to see them back."

But there is another note in that chord: "There are some people--the union militants, the troublemakers, the people who made threats and got nasty with us--that I wouldn't want to see back here under any circumstances."

That, really, is the major problem facing the government now: to find a way to bring back a few thousand of the fired controllers (not all of them are needed in any case) without opening itself up for lawsuits by those not returned to work.

I'm not even sure it is possible to do. As one working controller at the Washington center put it, "As long as there's an ACLU--as long as there's a lawyer with a breath in his body--selective rehiring will mean lawsuits."

A number of suggestions have been made. For instance, there is the proposal that the president pardon the offenders then put the controller vacancies up for bids, leaving it to the Federal Aviation Administration to hire back those who wanted to come back.

Another suggestion is to give the non- striking workers in each tower veto power over who can come back to work. Still another is to eliminate those strikers against whom harassing tactics can be proven.

And in each case the problem is the same: the disagreeable strikers are, in general, just as competent as the merely misguided ones, and there is no litigation- free way of excluding them--unless, by some miracle, every one of the strikers could be induced to waive his right to sue.

Still, there are enough people who want the matter resolved to convince me that it can be done. And if it can be done, it ought to be done.