A confidential warning dispatched from congressional critics of the prospective SALT II agreement only intensifies this dilemma of Western Europe: It regards a critical part of the treaty with horror yet cannot raise a whisper in protest.

The warning, a memo sent to serious Western European politicians, ask for more than a whisper. It wants a shout from across the Atlantic against the proposed limitation on ground-launched cruise missiles. Otherwise, the silence from Europe will be used to promote Senate approval of SALT II. Indeed, the Europeans are becoming entwined in Carter administration strategy for winning the two-thirds vote needed for ratification.

Yet, European political leaders have avoided public criticism of cruise-missile limitation. A clear explanation for silence comes from a senior West German diplomat: "We are linked to you 100 per cent, a condition that discourages argument."

The European dilemma is part of broad strategy in gaining Senate approval. Senior administration officials have privately given up any hope that Henry Jackson, leader of the Senate's defense-oriented Democrats, will support the treaty that is emerging from strategic arms limitation talks in Geneva. With an expected 30 out of 38 Republican senators aligned against the treaty, Jackson and three other Democrats could block ratification.

The administration's strategy against such odds is to pose the catastrophe of Senate rejection of a new treaty. At high levels of the State Department, there are tentative plans to hlep convince the Senate by getting European members of NATO to declare the necessity of the treaty.

What actually disturbs the Europeans more than possible rejection of the treaty is the 600-kilometer (360-mile) limit on ground-launched cruise missiles. In private, the British and Germans are pressing hard for a 2,000-kilometer (1,200-mile) range that would deal with new-generation Soviet weapons and reach Communist secondechelon reserves deep inside Eastern Europe and Western Russia.

The 600-kilometer limit is contained in the three-year protocol attached to the treaty. But political pressures in the NATO democracies would make it nearly impossible to break the ban after three years. This point is made in the confidential warning from Capitol Hill critics of SALT.

Secretary of Defense Harold Brown himself conceded this fast in typically frank conversation with reporters last week. "Clearly, at the end of that time [the three years of the protocol] there will be political pressures that will urge continuation of limitations."

Nevertheless, Brown was trying hard to reassure the Europeans at the recent NATO meeting in Brussels. He hinted strongly that the United States would not accept any limit on the right to transfer cruise-missile technology to NATO allies. He added that the range limit would apply only to deployment - not to testing - of ground-launched missiles.

At Brussels, both Brown and Secretary of State Cyrus Vance tried to paint a rosy picture of European acceptance of SALT II. The reality is that the Germans and British fear that the treaty will be the first dangerous step toward "decoupling" defense of the United States from the defense of Western Europe. One Western European defense expert last week strongly implied to Zbigniew Brzezinski, the President's National Security Adviser, that the cruise-missile limitation would actually result in "decoupling."

The mere thought of "decoupling" gives the Europeans the shakes. Could they then be forced into political accommodation ("Finlandization") with the Soviet Union? The Gaulist alternative of the French is to stay clear of SALT II entirely, neither endorsing nor rejecting but keeping all options open.

Consequently, the French are studying independent development of their own cruise missiles in the 2,000-kilometer range. But apart from the possibly unbearable cost, France (even collaborating with Britain and West Germany) may luck the necessary technology for targeting.

Instead, the warning from the Capitol Hill SALT critics urges a public campaign for language making absolutely clear that after the three years expire, NATO has the specific right to deploy 2,000-kilomater cruise missiles. Paul Warnke, chief U.S. negotiator, has been urging the Soviet to accept murky language in the protocol designed to ensure European passivity and help the push for Senate approval. Signs so far are that the canny Warnke is correct.