By MELVIN R. LAIRD

Mr. Laird was secretary of defense (1969-73) and counselor to the president for domestic affairs (1973-74). He served nine terms as a Republican representative from Wisconsin.

Now that Chuck Hagel has started work as secretary of defense, he may want to revisit his assertion at his confirmation hearing that he “won’t be in a policy-making position.” As someone who once served in the same capacity at the Pentagon, I can attest that being the defense secretary requires making policy whether or not the incumbent thinks it’s part of the job description.

In my very first month at the Defense Department in 1969, I proposed changes in our chemical- and biological-warfare policy. The changes were effected. Deputy Defense Secretary David Packard and I worked together to change U.S. policy in the Vietnam War from “Americanization” of the conflict to “Vietnamization,” turning over the main combat role to the South Vietnamese military. The Laird-Packard team announced that Defense would work to end the military draft that had been the law since 1939. We proposed the personnel policy of the All-Volunteer Total Force military and outlined the implementation process that culminated in the end of the draft in 1973.

The reversion of ownership of Okinawa to the Japanese was no small policy question—and it was delegated to the Defense Department by President Nixon. The transfer took place in 1972. The Pentagon handled another significant U.S. policy change in the Pacific, negotiating new defense agreements with Japan and South Korea that included military burden-sharing and an agreement that extended the U.S. nuclear shield, obviating the need for Japan and South Korea to start their own nuclear-weapons programs.

Also in South Korea, the U.S. in 1971 began the withdrawal of 20,000 troops from the demilitarized zone, a policy that the Defense Department executed over the objections of some in the Nixon administration. The Koreanization military program was supposed to continue, but no major U.S. troop-level reductions have been made since. Perhaps Mr. Hagel, if he decides that policy-making is in his purview after all, should revisit the subject.

The Obama administration wants to make strides in nuclear disarmament—a policy realm where the Defense Department’s input is vital. During negotiations for the country’s two major Strategic Arms Limitation Talks with the Soviet Union in the late 1960s and early 1970s, my views were conveyed by my personal representative at the talks, Paul Nitze. I had prevailed upon my friend Paul, the former deputy secretary of defense, to return to the Pentagon for this express purpose. Our policy input for the Salt negotiations was significant, and National Security Adviser Henry Kissinger relied on it even at times when the Defense Department’s wishes ran counter to advice from the State Department.

Formulating and exercising policy is a vital aspect of what goes on every day at the Defense Department. The country’s military leaders offer their wisdom to the defense secretary and rely on him to mold their input into useful policy. Likewise, the president and the rest of the national-security apparatus, including Congress, need the defense secretary’s policy counsel.

To be effective, the secretary of defense needs a strong policy-oriented staff, both military and civilian. Mine included Larry Eagleburger, who would later become secretary of state in the George H.W. Bush administration. I put him in charge of International Security Affairs at the Pentagon, and he was an invaluable adviser. Likewise, Gen. Bob Pursley, my military assistant, who had also served defense secretaries Robert McNamara and Clark Clifford, made exceptional contributions.

I hope that even if Mr. Hagel isn’t himself disposed toward policy-making, he picks a solid staff on that front—because eventually he will need it. If the country is going to maintain an effective approach to national security, it is difficult to imagine one that doesn’t involve the secretary of defense and the Defense Department in a comprehensive and dynamic policy role.

Mr. Laird was secretary of defense (1969-73) and counselor to the president for domestic affairs (1973-74). He served nine terms as a Republican representative from Wisconsin.