Perhaps the reason former secretary of agriculture John Block ''never once'' got the impression ''that veterans were being given the short end of the stick'' during his Cabinet days is that veterans' issues rarely made it to the discussions of the Cabinet room. They still don't.

Block's principal objection to creation of a Department of Veterans Affairs is that it ''will reduce the Cabinet's effectiveness.'' The opposite is true.

As national direction and policy are developed in critical matters such as AIDS, homelessness and the increasing demand for long-term care for older Americans, who better to advise the president than the agency at the forefront of innovation and research in these areas? As health care policies are examined, who better to advise the president than the agency that operates the free world's largest health care delivery system and provides training to half of the nation's practicing physicians?

No, adding this particular member to the Cabinet can only improve its effectiveness. There is now a serious void in this important advisory and policy-making body. Cabinet members are too busy with their own constituencies to give much thought to how greatly veterans' programs affect national policy in areas such as health care, housing, education, employment and rehabilitation.

I have no doubt that the secretary served farmers well. During his five-year tenure as head of the Department of Agriculture, agricultural expenditures rose from $11.3 billion to $31.4 billion -- an increase of 177 percent. However, it is doubtful that he is aware of the cost-containment measures in veterans' programs enacted by Congress during the past 10 years.

Block argues that because he and other veterans have held Cabinet offices, veterans have gotten their due. However, the vast majority of veterans who are served by the VA today have little in common with John Block. Today, most of the VA budget goes to those who were disabled in service, a distinct and honored minority of veterans, and those who are unable to afford basic necessities, chief among them health care.

''Organizational consolidation'' is not and never has been a reason for upgrading the VA. The administrator of veterans affairs has a tremendous responsibility for an array of programs that were long ago consolidated. A Cabinet that attempts to set national policy without this experience is necessarily weaker.

G. V. (Sonny) Montgomery

The writer, a Democratic representative from Mississippi, is chairman of the Committee on Veterans' Affairs.