"VELVET ON IRON" IS an apt metaphor to describe the diplomacy of Theodore Roosevelt and a nice change from that simplistic Big Stick we've been hearing about for so long. This new study by Frederick W. Marks III is the most important book in its field since Howard K. Beale's Theodore Roosevelt and the Rise of America to World Power (1956). Indeed many readers will judge it superior to its predecessor in its elegance, brevity and courageous originality. Others may find Marks' interpretations old-fashioned, even reactionary, in an age when we have to rely on ice-hockey teams to uphold our national honor.

This does not mean that he admires raw militarism; he argues convincingly that TR did not either. What principally concerns him is the velvet glove cushioning the iron fist, the consummate delicacy of touch which made Roosevelt one of history's master diplomats. Marks quotes as an epigraph a typical presidential injunction to Congress: "The Golden Rule should be . . . the guiding rule of conduct among nations as among individuals." But TR had an animal readiness to whip the glove off and punch when provoked, a quality commended in a second epigraph chosen from Thucydides: "Men secure peace byusing their power justly and by making it clear that they will not allow others to wrong them."

Velvet on Iron is divided into five separate but interrelated essays. The first, "Roosevelt in Context," achieves at once an imaginative feat impossible for most modern historians, namely the evocation of a vanished time and a half-forgotten personality, in prose undistorted by hindsight. Quickly, deftly, Marks describes the world scene that greeted TR at the beginning of the century. There was a gradual thaw in relations with Great Britain, which would soon accelerate, thanks to the president's wide circle of acquaintance in the Houses of Parliament. There were distant, but ominous rumblings in the East (marked, in an interesting parallel to 1980, by Russian penetration of Afghanistan and Iran). Closer to home, the Mikado was casting avaricious eyes on Pearl Harbor, while the Kaiser did the same on France's abandoned canal cut in Panama. This last threat, which TR regarded as part of a genuinely dangerous program of German aggrandizement in the Western Hemisphere, has been discounted by posterity, largely because of lack of documentary evidence in German archives. But Marks shows that it was real.

Here, and even more so in his next essay, "The Question of Credibility," he transcends the negative inferences of the merely academic. Far from being dauanted by lacunae (that bane of diplomatic research, endemic to all state archieves) he reasons correctly that absence of information is often a sign of its suppression. When parallel gaps appear in the records of other countries, his detective instincts are aroused. Indefatigably (this book is the result of three years of scrutiny of 58 archieves in the United States, Canada, Britain, and both Germanys), Marks digs "around" the hole, letting specks of circumstantial evidence fly where they may. Gradually, as dust revealed the shape of H.G. Wells' Invisible Man, the specks reveal the outline of some diplomatic ghost which Roosevelt, or the Kaiser, or both sought to erase from history.

The most dramatic example of this technique is an analysis of the Venezuela crisis of December 1902. Roosevelt privately boasted, long after leaving the presidency, that he had threatened Germany with war unless she agreed to accept arbitration of her monetary dispute with Venezuela. The danger, in his opinion, was that the Kaiser might use the dispute as an excuse to occupy Venezuela, thus violating the Monroe Doctrine, which TR held in greater reverence than the Nicene Creed. The Kaiser did in fact accept arbitration, after a period of suspense that would have been as terrifying as the Khrushchev-Kennedy confrontation over Cuba in 1962 -- had the world been permitted to know about it. Even so, skeptical historians have been reluctant to believe that TR, with his small navy and army, could so aggressively manipulate a Wilhelm II. There is nothing in the archieves to indicate that Germany did not act out of unilateral high-mindedness.

Professor Beale was the first modern authority to suggest that TR probably did issue that secret ultimatum, and Marks' further argument makes this view almost conclusive. But again, his interest is not so much in power play as in the extraordinary pains TR took to conceal his diplomatic triumph -- pains exceeded only by German ministers in their efforts to conceal the Kaiser's defeat. (One volume of Berlin dispatches actually ends in mid-sentence at the onset of the crisis, resuming hundreds of blank pages thereafter; identical gaps appear in the records of Secretary Hay.) Mark cites a dozen other examples of TR's stated willingness "to build a bridge of gold" for his diplomatic victims, allowing them graceful exits from ugly situations -- so much so that they often earned greater applause than he. The only conclusion to be drawn from such abundant evidence is that Roosevelt was a statesman of the highest caliber, concerned with long-term results rather than temporary personal glory.

One turns, accordingly, with anticipation to "The Moral Quotient," Marks' essay dealing with the Panamanian Revolution of 1903, to see if he can possibly expunge this generally accepted blot on TR's record. Marks has the courage, some would say temerity, to see the affair through TR's spectacles as "one of high moral principle." He shows us a state bound to Colombia by the most fragile political and geographical ties, intermittently obtaining for only 53 years of its five-century history. With its own social identity, its separate currency and post office systems and its unique interest in an interoceanic canal, Panama had rebelled against Colombia annually, on average, throughout the uneasy alliance. Moreover, it was in 1903 being held to American ransom by the Colombian dictator Jose Marroquin, whose ambassador had earlier the same year signed a treaty allowing Roosevelt to build the canal. As Marroquin's canal purchase price escalated, so did TR's temper, and so did Panama's separatist fervor. When Marroquin called a puppet congress in Bogota and forced it to reject the treaty, Roosevelt saw no moral alternative but to recognize the revolution which inevitably broke out on the isthmus in November. Not to do so, he believed, would guarantee "endless guerilla warfare" in Panama, of the sort that has subsequently become the anemia of 20th-centruy authoritarianism. When Marroquin frantically offered to approve the treaty after all, if the United States would help crush the revolution, "this only confirmed TR's suspicions of double-dealing and steeled him all the more in his support of Panamanian independence."

Difficult as it is for the modern mind to comprehend the old diplomatic qualities of pundonor, politesse, and aristocratic disdain for transgressions of the moral code, Marks succeeds in making us admire them. TR was as richly endowed with these qualities as any Victorian patriarch, yet at the same time he showed brute wilingness to particpate in the new century's global power struggle. His virtuoso performance as the peacemaker of Portsmouth, combined with shrewd exploitation of the news media, made him, as Marks notes, "undoubtedly the most internationally popular of all our presidents." It is significant that his greatest admirers included the Russians, the Germans and the Japanese, all of whom periodically felt the iron beneath his velvet glove, and their admiration was tinged with respect for America as much as for himself. Herein lies Theodore Roosevelt's enduring achievement as diplomat and statesman. "Even in private life," Marks writes, "he acted . . . on the assumption that respect was denied to the weak more quickly than it was withheld from the strong, and that the display of power would alone permit him to practice a superior brand of ethics. Once this principle had been established on the individual level, it required little imagination to apply it to nations."

The merits of this book are such that one hesitates to point out two major inadequacies, namely, failure to explore French and Japanese sources. Perhaps Marks will one day use these archives in the course of a more detailed history of Theodore Roosevelt's foreign policy; if so his work should prove definitive.