At the beginning of his 12-day European swing US Vice-President George Bush is focusing more on defending new NATO missile deployments than on displaying American flexibility in Euromissile arms control.
In a speech in West Berlin Jan. 31 billed as the highlight of his trip, he stressed that in order ''to be credible in our arms negotiations, the alliance must be united in its determination to deploy (planned new nuclear missiles) if necessary.''
Between now and Feb. 10 Mr. Bush will be repeating this message in all five of the NATO lands scheduled to accept the new missiles - West Germany, Italy, the Netherlands, Britain, and Belgium - as well as in France and in Geneva, where he will meet with the chief US and Soviet arms negotiators.
Vice-President Bush and West German Chancellor Helmut Kohl agreed pubicly Jan. 31 that the American arms proposal known as the ''zero option'' - under which NATO will forgo deployment of close to 600 new nuclear weapons planned for December if the Soviet Union dismantles its current 300-plus SS-20 missiles - would be the best possible outcome of the current US Soviet arms-control negotiations.
This is not an all-or-nothing affair, the two added, however. Bush also repeated President Reagan's vow that the US will consider any serious Soviet arms-control proposal.
This nod in the direction of European desires for more give in the US negotiating position might help Kohl in the crucial campaign leading to the March 6 general election here. In this campaign Kohl is being charged by political adversaries with being too supportive of the American Euromissile position and new NATO deployments, and without exerting stronger pressure on Washington to negotiate arms control seriously with the Soviet Union.
The main thrust of Bush's Berlin speech, however, was less a display of American negotiating flexibility than a defense of America's year-old zero option position in the Geneva arms control negotiations. Europeans are increasingly looking for some flexibility in modifying the zero option as the test of American seriousness in arms control.
The important thing Bush asserted is to break the Soviet monopoly on intermediate-range nuclear missiles (INF) that can strike Europe. (Bush referred to this monopoly without specifying that it exists in land-based but not sea-based missiles, and without mentioning the independent French and semi-independent British missiles, which NATO considers outside the scope of the current American Soviet negotiations.)
The Soviet-European INF monopoly, Bush warned, seeks to break the linkage between the US and European security. If this linkage were to be broken, he added, the 38-year deterrence of war in Europe would be undermined.
In defending the NATO decision to deploy new nuclear missiles, Bush described and rebutted four peace-movement ''myths.'' He described these as:
* New deployments ''would change NATO's strategy.''
* The deploynment decision was ''thrust on an unwilling Europe by the United States.''
* Deployments would ''increase the alliance's reliance on nuclear weapons.''
* The missiles ''would be a step toward nuclear war-fighting and to war-fighting confined to Europe alone.''
All of these Bush regarded as untrue.
He said the deployments are essential precisely in order to maintain the security linkage between the US and its allies. The NATO decision was not an American initiative but ''a response to widespread concern, especially in Europe , over the alarming buildup of Soviet INF forces.''
Further the new deployments would still leave fewer allied nuclear warheads in Europe than there were in 1979 because of the withdrawal since 1979 of 1,000 nuclear warheads from Europe. Besides, he continued, NATO nuclear deployments are only for deterrence - not for fighting.
''We are not preparing to fight a nuclear war,'' Bush said flatly.