Protecting Persian Gulf oil ranks right after defending North America and North Atlantic Treaty Organization countries on the Reagan administration list of military priorities, according to Pentagon guidance written for the armed services.

The guidance fleshes out a statement made in a recent policy speech by President Reagan's national security adviser, William P. Clark, who said "we must establish priorities for sequential operations" in a global war since the United States could not "successfully engage Soviet forces simultaneously on all fronts."

Rather than try to build a fight-them-everywhere military machine, Clark said "the president has established priorities." Clark did not spell them out, but the guidance to the armed services for the five-year period 1984 through 1988 goes a long way toward doing so.

"Because our forces for the mid-term are insufficient to achieve all military objectives simultaneously," states the final draft of the guidance written by a number of Pentagon officials for Defense Secretary Caspar W. Weinberger, "the strategy" for containing the Soviets in a war "has an inherent degree of risk and will require difficult choices involving sequential operations . . . .

"While recognizing that the political and military situation at the time of war will bear heavily on strategic decisions," continues the guidance, "the following priorities are provided for general planning in the event of a worldwide war with the Soviet Union:

"Defense of North America--including Hawaii, Alaska and the contiguous Caribbean Basin--followed by the NATO areas and the LOCs lines of communication leading thereto will have the highest priority.

"The next priority for general planning will give emphasis to ensuring access to the oil in Southwest Asia, followed by defense of U.S. Pacific allies and the LOCs for the Indian and Pacific oceans and the defense of other friendly nations in Latin America and Africa.

"U.S. actions in other parts of the world will be designed to protect essential U.S. interests, take advantage of Soviet vulnerabilities and divert attention and forces from Europe and Southwest Asia. U.S. counter-offensives, however, may well take place in these other parts of the world early on to take advantage of exposed enemy positions."

The ranking of priorities in the Pentagon paper--termed "this first complete Defense Guidance of this administration"--fits comfortably with those of past administrations, both Democratic and Republican. Part of the reason is that much of what ends up as guidance under the name of the defense secretary is written by Pentagon careerists.

Some of those professionals said they had more opportunity this time around to write drafts of the guidance than was the case last year when the Weinberger team seemed to them to be rushing with little thought into making policy statements.

Even so, the new guidance document, like the ones before it, is more the rough shape of what the defense secretary wants the military to do rather than any detailed blueprint. And this year, as in other years, there is only so much money in sight, meaning the generals and admirals will not be able to buy all the forces they believe they would need to transform the civilian rhetoric into military forces.

The fiscal 1984-88 Defense Guidance calls for stretching forces between NATO and the Persian Gulf, arguing that the two are connected strategically. Provide forces, directs the guidance in this connection, "that can be used both in the direct defense of NATO and in the defense of allied interests in Southwest Asia."

Specifically, states the guidance, improving "reconnaissance, surveillance and airborne warning and control and fighter defense for the southeastern part of NATO would in themselves have a direct application to defense of the upper Persian gulf and so would increase the deterrent."

Besides looking for ways to stretch existing forces to cover more than one region, the guidance sees potential gain in causing Soviet commanders to question whether they could count on Eastern European armies in a war against the West.

"Given the sustained buildup of Warsaw Pact capabilities and the heightened threat to allied interests in Southwest Asia," states the guidance, "we must develop more effective linkages with the people of East Europe so as to deny Soviet confidence in the reliability of her allies."