A partial text of remarks by Secretary of State George P. Shultz in briefings for members of the Senate and House:

. . . We are in Lebanon because the outcome . . . will affect our position in the whole Middle East. To ask why Lebanon is important is to ask why the Middle East is important . . . .

The United States is involved in the quest for peace in the Middle East because it is a region of vital strategic and economic importance for the free world, because it is an arena of competition between the United States and the Soviet Union, because we have a deep and abiding commitment to Israel and an interest in strengthening the trends of moderation in the Arab world and because our role of leadership in Middle East diplomacy is a reflection of America's responsibility as a world leader.

The crisis in Lebanon cannot be isolated from the broader Middle East crisis . . . .

The contest in Lebanon involves many of the same parties that figure in the broader Middle East drama: moderate elements that yearn to settle their differences peacefully and radical elements that both preach and practice hatred . . . .

The issues at stake in Lebanon are therefore some of the same issues at stake in the search for Middle East peace: questions of security, of respect for national sovereignty and the viability of peaceful solutions.

At stake . . . is the fate of the second moderate Arab country to negotiate a major agreement with Israel. I should not have to elaborate on what it would mean for the overall peace process, and for Israel's long-term security, if the assault on this moderate government should succeed . . . .

At stake is the right of a small country like Lebanon to decide for itself how to achieve its sovereign objectives free of outside pressure, threat or blackmail.

This is a basic principle of international law and international morality that is vital not only to the future of the Middle East but to the kind of world we want to live in over the remainder of this century.

If America's efforts for peaceful solutions are overwhelmed by brute force, our role in the world is that much weakened everywhere. Friends who rely on us will be disheartened and will be that much less secure. Moderates in the Arab world whom we are encouraging to take risks for peace will feel it far less safe to do so. Israel's security will ultimately be weakened.

If we are driven out of Lebanon, . . . the message will be sent that relying on the Soviet Union pays off and that relying on the United States is a fatal mistake.

This is, of course, the opposite of the message that we want to convey . . . .

If we are driven out of Lebanon, it will be a major blow to the American position in the Middle East. If we want the role and influence of a great power, then we have to accept the reponsibilities of a great power.

If we as Americans decide we do not want the role and influence of a great power, then I shudder to think what kind of world of anarchy and danger our children will inherit.

. . . Our goal in Lebanon is a political settlement between the government and the various confessional groups, aiming at a broader-based government that can extend its sovereign authority throughout the century.

In these circumstances, we envisage the withdrawal of all foreign forces, as well as security arrangements to assure . . . Israel's northern border. This process of political accommodation is an urgent task. It should be a priority responsibility of Lebanon's leaders and Lebanon's people. It is also one of our high priorities.

One step toward this goal was the May 17 agreement between Lebanon and Israel. It provides a framework for cooperation between Lebanon and Israel, and it offers the only existing arrangement for assuring Israeli withdrawal while addressing the basic problem of border security that created the Lebanese crisis . . . . We . . . look to the day when it will be implemented.

Our goal is a political solution, not a military solution. Yet the presence of our Marines has been a crucial pillar of the structure of stability that is needed to make a political solution possible. Our strategy is built on several such pillars:

* Our Marines are part of a multinational peace-keeping force . . . symbolizing broad international support for the legitimate government of Lebanon.

* Backing up our Marines is a powerful offshore naval force, which has fired in defense of the Marines . . . . Our allies also have naval assets in the eastern Mediterranean and have used them.

* In the military dimension, the primary responsibility rests on the Lebanese armed forces, which we helped to train and equip. The army has proven to be a brave and effective fighting force and is getting stronger . . . .

It is more than a match for its Lebanese opponents. Its difficulties have come when it was under assault by forces protected, armed, supported and encouraged by Syria.

* The Lebanese government has the support of moderate Arabs, which can only be strengthened by a successful effort of national reconciliation.

* Israel, too, remains a key factor in Lebanon, and we need its constructive efforts in support of the Lebanese government and the process of reconciliation. Israel has leverage with some of the confessional groups, and we hope it will use this leverage . . . encouraging political accommodation.

Syria and its surrogates, of course, have been obstructing both our efforts to get foreign forces out and . . . to promote political accommodation. No one questions Syria's legitimate security concerns with respect to Lebanon.

But Syria . . . has been unwilling to negotiate . . . . over how to reconcile its security concerns with Lebanon's sovereign right to decide its own future. Instead, Syria has declared a kind of "Brezhnev doctrine," whereby countries in its orbit have no sovereign right to make any decision that displeases it.

We achieved a cease-fire on Sept. 26, however, by demonstrating that there were limits beyond which we could not be pushed. The achievement of this cease-fire showed that we have the assets to maintain a stable balance in Lebanon so that the government's opponents cannot steamroll the political negotiations. We must maintain that balance.

. . . The bipartisan support shown . . . on the war powers issue was an important contribution, dispelling doubts about our staying power and strengthening our hand.

. . . President Reagan is determined that we will not be driven out of Lebanon by the enemies of peace. We will stay, and we will carry out our mission . . . .