Busy minds should not be taxed for inconsistency. But for George Will to criticize a presidential candidate for inaccuracy {"The Way the Media Treat Jackson," op-ed, Jan. 28} sounds like a drug peddler bemoaning the declining morals of the young.

Mr. Will, after all, regularly hawks the hallucinogenics of Ronald Reagan, who has contributed more falsehoods, distortions and just plain howlers to our public dialogue than any leader in recent memory. Most recently, Mr. Reagan informed the Tower commission investigators that he had authorized an arms sale to Iran, then that he had not and, finally, that he just couldn't remember. A pundit suggested that he wanted to make certain that the committee had all sides of the story. This may explain what Mr. Will meant when he wrote in 1981 that ''Reagan's foremost achievement has been in convincing the country not that he knows the future, but that he knows his own mind.''

Mr. Will embraces Mr. Reagan not because he gets ''rudimentary things right,'' but because Mr. Will endorses the president's politics. He has labored prodigiously for the Reagan cause, even going so far as to appear on network television to praise Mr. Reagan's performance in a debate, after spending hours helping him to prepare for it.

In this light, was Mr. Will's shabby treatment of Jesse Jackson on national television perhaps in the service of the same cause? Does Mr. Will oppose Mr. Jackson because he questions the accuracy of his statistics or because he opposes the direction of his program and fears his ''considerable support'' and ''substantial influence''?

Mr. Will's questions appear designed to detract from rather than to probe Mr. Jackson's positions. Mr. Will scored debating points, but Mr. Jackson is right on the merits. He is correct to say that more than 50 cents of the tax dollar is devoted to military purposes, factoring in a fair share of interest on the national debt. When Congress divides up discretionary spending, more than half of it goes to the military. (Mr. Will's 28 cents comes from adopting Lyndon Johnson's ploy of combining the trust funds with the discretionary budget to mask the cost of the military.) Mr. Jackson's point is that our real security demands that we change our priorities so we can rebuild our economy.

More than 30 million workers have been displaced since the mid-'70s. Many have been forced to accept jobs with lower wages and fewer benefits. In the midst of the Reagan miracle that Mr. Will likes to tout, the real family income of a majority of households has declined.

Mr. Will's final question -- ''Would you support measures such as the G-7 measures in the Louvre accord?'' -- made even his ABC colleagues wince. Its clumsy wording suggests that the eloquent Mr. Will labored to invent a question purposefully obscured with technical shorthand to spring on Mr. Jackson on a Sunday morning talk show. Had Mr. Will been more interested in exploring Mr. Jackson's views than in displaying his own cleverness, he might have found that Mr. Jackson talks cogently about the need for industrial nations to act jointly to reflate the global economy and, in that context, stabilize the dollar.

Mr. Will's suggestion that Mr. Jackson benefits from a double standard also rings false. No matter what his prominence in early polls, Mr. Jackson was tagged with a ''can't win'' label affixed to no other candidacy no matter how obscure. His substantive positions, many of them original, have been virtually ignored by a press content to focus on his one-liners. Mr. Will thinks this benefits Mr. Jackson because he assumes the country still marches to a conservative drummer. In this, too, he is wrong.

These are the sunset hours of the conservative reaction. The party is over; the bill is coming due. But we need not let Mr. Will's understandable distemper distract us from the important debate about changing the direction of the country and rebuilding America from the bottom up. Jesse Jackson has been and will be central to that debate.

ROBERT L. BOROSAGE Washington

The writer is director of the Institute for Policy Studies and an adviser to the Jackson for President Campaign.