Not long ago Congress voted to finance a pending highway bill by denying billions of dollars to veterans suffering from tobacco-related illnesses. Shortly afterward veterans groups were stunned to discover that the lawmakers actually went further than that and declared any veteran who smoked on active duty could be considered to have engaged in "willful misconduct."

That is the same standard that the Department of Veterans Affairs uses to deny benefits to alcoholics and drug abusers. The comparison has made veterans groups livid and yesterday they vowed to force a second vote on the issue.

The veterans groups delivered their complaints to President Clinton at a Memorial Day breakfast, but they acknowledged yesterday there is little likelihood that he will veto the highway measure. As a result, the groups are trying to stir up their members enough to lobby Congress and force major changes through a "technical corrections" bill, which normally is designed to make uncontroversial fixes in legislation.

A spokesman for the House Transportation and Infrastructure Committee said Congress will consider the technical corrections bill soon. But many members may be unhappy to have to vote directly on the veterans issue.

Besides denying compensation, the highway bill also may have gone so far as to block the VA from taking care of veterans who become ill on active duty with tobacco-related illnesses, such as lung cancer and heart ailments, a VA official suggested. The VA long has accepted those individuals for care and benefits, but a spokesman said VA lawyers are now debating whether the new law will allow their continued care.

Despite rulings by VA lawyers that say the department must consider tobacco-related illnesses service-connected, the department has rejected virtually all the claims it has processed for compensation for smoking-related ailments.

What the Congress has done is to "retroactively redefine conduct that was not only legal but was also encouraged by the military," said Phil Budahn, a spokesman for the American Legion, the nation's largest veterans organization. He and other veterans noted that the military provided free cigarettes to service personnel as recently as the Vietnam War.

In late 1992, a Bush administration appointee declared that the VA should pay for veterans' smoking-related illnesses. But the Clinton administration has sought to distance itself from that position, because of the expected cost of billions of dollars. Instead, it called for legislation to overturn that ruling by the VA's general counsel and a subsequent ruling by its own appointees that made it easier for veterans to file tobacco claims.

Until the highway bill came along, Congress had avoided the issue. Because denying the tobacco benefits would create a budgetary savings of as much as $ 23.8 billion over five years, promoters of the highway bill latched on to the idea as a way to pay for increased highway spending.