Senate Majority Leader Robert J. Dole (R-Kan.) has written the White House, urging President Reagan to nominate acting Social Security Commissioner Martha A. McSteen as permanent commissioner instead of ousting her in favor of a political nominee.

McSteen, a career civil servant, was named acting commissioner 16 months ago by Health and Human Services Secretary Margaret M. Heckler, but the White House never sent her nomination for the permanent job to the Senate. Instead the White House is considering nominating Dorcas Hardy, assistant secretary of HHS for human development services. Hardy, who is known as a Reagan loyalist, and served in his administration when Reagan was governor of California.

Expressions of support for McSteen also came from J.J. (Jake) Pickle (D-Tex.), chairman of the House Ways and Means subcommittee on Social Security, and Edward R. Roybal (D-Calif.), chairman of the House Select Committee on Aging.

In his letter to John S. Herrington, director of the office of presidential personnel, Dole said McSteen "has capably been performing the duties of acting commissioner for over 15 months. During this period of time she gained the respect of those of us on Capitol Hill, as well as those organizations with whom she has been involved." He said that McSteen "has both the experience and the ability to manage the mosaic of programs within the Social Security structure."

Dole added that "last year I had the opportunity of working very closely with McSteen and her senior staff trying to iron out legislation that would make the decision-making process more responsive to the needs and concerns of the disabled. During this time, Ms. McSteen continued to offer invaluable guidance as well as continued support for the president's views regarding the implementation of this important program."

In a letter to Heckler, Pickle said it is important to protect Social Security from "capricious" political manipulation and changes that are "wholly politically inspired" because Social Security needs "experienced, knowledgeable and nonpolitical" leadership. He asked Heckler to clarify the nomination's status.

Roybal also expressed concern that Hardy's nomination could "politicize the Social Security Administration." He said Hardy is a "capable person," but that "Mrs. McSteen has been working for the Social Security Administration" since 1947, "as long as Ms. Hardy has been alive."