Donald Rumsfled, who occupied several Cabinet and White House staff positions for presidents Richard M. Nixon and Gerald R. Ford, shows every sign of wanting to come back to Washington -- this time in the Oval Office. Rumsfeld, 53, who replenished his personal finances as president of the G.D. Searle & Co. drug firm, has been hitting the speaking circuit heavily in recent months and does not demur at speculation in GOP circles that he would like to enter the 1988 presidential race.

The former Illinois congressman, whose last Washington tour was in the Ford administration as chief of staff and later secretary of defense, says, "The question of my running comes up almost every time I speak, and I tell people it's something I will have to address in the next year's time."

After leaving Searle this year, Rumsfeld turned down other business posts and overtures to run for office in Illinois. But he has addressed GOP and civic gatherings from California to New Hampshire, has taken a leadership role with three conservative policy groups -- the Rand Corp., the Institute for Contemporary Studies and the Committee for the Free World -- and is readying a series of articles on defense and domestic issues.

Associates say Rumsfeld -- who toyed with a presidential candidacy in 1979-80 -- believes that no one, including Vice President Bush, possesses the kind of hard-core support for 1988 that Ronald Reagan enjoyed going into 1980. If he continues to find encouragement on his travels, associates expect Rumsfeld to join the GOP field after the midterm elections next November.