On April 19,1929, Chief Boatswain's Mate Hubert E. Wilbur and Surfman Orville M. LaGrant, both members of US. Coast Guard, began routine patrol of Niagara River. The patrol, which nearly ended in bloodshed, provoked an international incident that took almost year to resolve. The episode resulted from United States' arming its borders to an unprecedented extent in an effort to win Canadian government's assistance in enforcing Prohibition laws. Perceived by Canadians as an integral part of American policies that took Canadian sovereignty lightly arming of border jeopardized U.S. treaty obligations and brought extraordinary violence to border communities. (1) This federal activity south of border threatened to negate local efforts to enhance along-successful borderlands community. Thus, Wilbur and LaGrant's experience illuminates seldom-told story of cross-border relations between United States and Canada. A number of historians point out that Prohibition was singularly divisive factor in relations between Canada and United States. The American desire to assert greater control over U.S. borders, they note, often conflicted with growing Canadian nationalism that sought to assert an independent identity. These historians approach issue in variety of ways: Richard N. Kottman comments that Canadian support for assisting Americans with Prohibition enforcement varied regionally. His analysis pays little attention to events on interior border as factor in Canadian-American relations, however; he focuses instead on U.S. Coast Guard's sinking of Nova Scotian schooner I'm Alone in Gulf of Mexico in 1929. Stephen T Moore elaborates on cross-border community between Washington and British Columbia, noting that violent activities of liquor hijackers, coupled with evidence of government corruption, threatened to disrupt local heritage of cross-border cooperation. That disruption, in turn, led to regional support for cooperating with United States in Prohibition enforcement. Sean T. Moore has considered ways in which outside law enforcement disrupted binationallocal economy in northern New York, causing locals to abandon support for Prohibition. (2) None of these historians takes into consideration extent to which United States tried to force Canadian public and political opinion into line with American government demands by posting heavily armed, uniformed military force along border. This article attempts to add another piece to puzzle. Prelude In public spectacle in summer of 1927, United States, Canada, and Great Britain showcased familiar story of cross-border relations. On August 7, 1927, before 100,000 people and an international radio audience that may have reached as many as 50 million, Edward, Prince of Wales, United States Vice President Charles G. Dawes, British Prime Minister Stanley Baldwin, Canadian Prime Minister William Lyon Mackenzie King, and host of other dignitaries (including governor of New York, premier of Ontario, and U.S. secretary of state) met at Buffalo to dedicate Peace Bridge, new commercial link facilitating automobile traffic between east coast of North America and interior. It was major international event. All of speakers praised 100-plus years of peace that had prevailed among United Stales, Great Britain, and Canada since War of 1812. The piers of bridge of friendship now replaced two hostile forts, Mackenzie King observed. Acknowledging recent exchange of ministers between United States and Canada, Secretary of State Frank B. Kellogg observed that between two countries there are no racial animosities, no great international antagonism, and that differences can be settled with exercise of tolerance and patience, and application of good common sense. Calling it a bridge of understanding, Dawes said that Peace Bridge had been built upon both the firm bedrock of Niagara, and peace of English-speaking peoples. …