What's behind the chummier US-Pakistan relationship

In three short years, the United States relationship with Pakistan has gone from peanuts to plenty.

After a deterioration in relations under the Carter administration, the Reagan administration has established close ties with Pakistan's President Muhammad Zia ul-Haq.

The Carter administration objected to President Zia's human rights record and focused on trying to keep Pakistan from developing a nuclear bomb. And then after the Soviet invasion of Afghanistan in January 1979, the Carter administration reversed itself and offered Pakistan $400 million in military and economic aid over a two-year period. President Zia dismissed the sum as ''peanuts.''

Half the money was to be in military sales credits which Pakistan would have to pay back. General Zia feared that acceptance of the aid would provoke India and the Soviets and jeopardize Pakistan's position in the nonaligned movement and among Islamic countries. The offer also failed to strengthen the US commitment to help defend Pakistan.

The Reagan administration has decided that a secure Pakistan is essential to the stability of the entire South Asian region, including the Gulf. It has proposed a $3.2 billion program for both economic and military assistance for Pakistan over a six-year period. Officials say that the ''multiyear aspect'' of this program is meant to underscore the US intention to prove itself a reliable, consistent partner.

The Reagan administration claims not to have slackened US efforts to control the spread of nuclear weapons. But officials say they hope to help eliminate the sources of insecurity which made Pakistan seek nuclear weapons in the first place. The proposed military aid to Pakistan is to enable that nation of 84 million to fend off incursions from Soviet-backed Afghan forces and to keep the Soviets from thinking they can easily coerce or subvert Pakistan.

But while the United States is no longer dealing in ''peanuts'' when it comes to Pakistan, it will take time and care to consolidate the relationship. The Pakistanis feel that all too often in the past, Americans have viewed themselves strictly as ''donors'' to Pakistan, with little consideration given to what Pakistan contributed to the relationship.