THERE ARE, as we understand it, two main reasons why Griffin Bell, Jimmy Carter's choice to be Attorney General, has been questioned so closely by the Senate Judiciary Committee this week. One is doubt about his commitment to a society free of institutionalized racial discrimination. The other is fear that his ties to Mr. Carter are too strong to permit him to run the Justice Department in a property apolitical way. While both are legitimate concerns, it seems to us that Mr. Bell's testimony over the past couple of days has tended to resolve them in his favor.

We will acknowledge at the outset that we were surprised, and not pleasantly so, when Mr. Carter, after all the heavy uplift of his campaign rhetoric on the administration of justice, ended up picking Mr. Bell. And the implausible praise Mr. Carter heaped on his candidate - "the best qualified person" in the country to be Attorney General - didn't exactly help. Even Mr. Bell, we hope and suspect, would readily admit that there are others better qualified than he. But laying aside for the moment the two specific items of concern about this selection, it can at least be said that Mr. Bell's qualifications are a hefty cut above those of many who have served as Attorney General over the past 25 years - never mind that the present incumbent is not among them. Mr. Bell has demonstrated in these hearings far greater knowledge and understanding of constitutional law and the problems of the legal system, for instance, than were displayed in comparable hearings by either John Mitchell or Robert Kennedy, to name but two.

As far as keeping politics out of the Justice Department is concerned, the intent of the Attorney General is far more important than his past connections or political enterprises. We believe Mr. Bell when he says he will try to run the place in an apolitical way. The test will be whether he can , and it seems to us that a former judge is likely to have a better chance than most to do so. Fulfilling this pledge, as he testified, is a matter of personal intergrity. And, in a perculiar way, Mr. Bell demonstrated some of that quality by refusing to take back what he once wrote about the nomination for the Supreme Court to Judge G. Harrold Carswell. It would have been easy for him to reupdate his past recommendation of Mr. Carswell and thus remove one argument raised against his own confirmation. But he has consistently said that he did it and that he must live with it, too.

On the issue of civil rights, it is true that Mr. Bell has never been an outspoken advocate of equal rights for all citizens, although few could fault what he said on the subject this week. But it is vital to remember that few outspoken advocates of civil rights survived politically in Georgia 15 to 20 years ago, when he was active in public affairs. Mr. Bell is proud, and rightly so, of what he did to help Georgia move toward school desegregation in the years from 1959 to 1961. Those actions may appear timid or even half-hearted by the standards of Washington (and also Atlanta) in 1977. But they were not timid or half-hearted in the days of closed schools, obstructed school house doorways and college campus riots.

As a judge, Mr. Bell handled more than his share of desegregation cases. Yes, there were some bad opinions and decisions. He did not move either as quickly or as far as civil rights movement wanted him to. But he did help get the job of desegregation done.

To some extent the concern about Mr. Bell's views on civil rights reflects a preoccupation with what the Justice Department should have been like in the past couple of decades, and not what it should be like now. Most of the needed civil rights legislation is in place. Some of it does need better enforcement. But our guess is that the focus of the department in the next several years is going to be on other aspects of the law, reforming the FBI, sharpening the attack on crime, and fashioning better ways of delivering justice to all citizens.

Even so, the inquiry into Mr. Bell's past record and present commitment on the question of racial justice has been useful. To be sure, it hardly seems possible that a Senate majority which has just chosen Robert Byrd, no less, to be its spokesman and leader will refuse to confirm Mr. Bell on grounds that he lacked ardor for civil rights laws in the past. But the Senate inquiry has nonetheless been both relevant and helpful. It has sharpened the public commitment of Mr. Bell and the senators to the pursuit of this nation's unfinished racial business.