Clearly it is not unreasonable for senators to receive a salary of $125,000. That, however, is not the issue. The manner in which the Senate voted the increase is just plain tacky. If political leaders would stop playing such games and would exercise forthright explanation and leadership, they might well find greater support on the part of the American people.Why can't Congress adjust its salary annually for inflation? That is the way most Americans receive pay increases. Had the Senate taken that action, there would have been no need for a $23,000 increase all in one year. James L. Caplinger, Mechanicsburg, Pa. Letters are welcome. Only a selection can be published, subject to condensation, and none acknowledged. Please address them to "Readers Write," One Norway St., Boston, MA 02115.