William Buckley has won his long fight with the TV performers union, the American Federation of Television and Radio Artists.

He never wanted to join the union in the first place, he says, but had to because the union told him that, it he didn't, his "Firing Line" program would not be aired by the stations around the country.

He protested, naturally. A court decision seemed to uphold him, then there was an appeal that seemed partially to uphold him.

Finally (in the U.S. District Court for the Southern District of New York) both the plaintiffs and the defendent agreed to discontinue the case, and the final agreement is that Buckley does not have to join the union, does not have to pay the union dues, or an equal sum in lieu of dues, and that the union will notify the stations that an employe does not have to join the union in order to keep a job.

Employers, experience sometimes suggests, are not all of them certified do-gooders, and if it were not for unions and their power or organized clout, a lot of workers would not now be buying spinach, but would be still struggling along on cornpone and sowbelly.

So there has not not been any great race, that I can see, to air the Buckley triumph. Is it the opening blow to destroy unions?

It may mean someting less sinister.

I notice a more or less gilt-edged liberal, Robert Maynard, now a freelance writer for this newspaper (folk rarely thought of as closet Birchers), has also run into trouble with the same union.

He says in the January-February issue of the Washington Journalism Review that his paycheck for a television appearance was not sent to him, but to the union, which held the check for some weeks. During that time, Maynard said, he was supposed to be making up his mind whether to join the union or not, with the extra little hint thrown in that if he ever expected to get paid for another TV appearance he had better join.

Like Buckley, Maynard began thinking of constitutional rights. When he asked the union why they had not at least told him they had his money, he says, "I swear she spat these words in my face: 'We are not obliged to tell you we have your money.'"

"Move over, Brother Buckley," he concluded. "There's room here for both of us."

Power goes to the head, and if you have it, whether you're a corporation or a union, arrogance usually follows.

All of a sudden you can tell everybody else to go buzz off.

Now the vice president's sidewalk, to get back to that . . .