There was also a parallel movement for annexation in Canada, compelled by its own internal factors so that its peaks and valleys of popularity did not always correspond to those in the United States.  However, agitation for political union was often more intense in Canada, and, barring a military invasion, it was there that the issue would be settled one way or the other.  Annexation fever rose in Canada in the mid-1880s, primarily because of economic distress.  Yet in contrast to Nast's cartoon, it was centered in Ontario and Manitoba and gained little support in either the Maritime Provinces or the United States.

The provocation for the cartoon was a dispute between Canadian and American fishermen, which had been a persistent problem in British-American relations for over a century.  On July 1, 1885, the Republican-controlled U.S. Senate abrogated the fisheries articles of the Treaty of Washington (1871).  The articles had allowed American fishermen, mainly from New England, to fish in Canadian bays and other inland waters in return for Canadian fishermen being allowed to export fish duty-free to the United States.  The latter provision was the sore spot for protectionist politicians, particularly Republicans from New England, that led to the repeal.  In response, Canadians started seizing American ships fishing in their waters in violation of the newly abridged treaty.

In March 1887, Congress exacerbated the conflict by passing the Retaliation Act, which authorized the president to prohibit Canadian goods and ships from entering American ports if the harassment of American fishermen continued.  President Grover Cleveland, a Democrat who favored low tariffs and improved relations with Britain, signed the act but chose not to enforce it.  Beside supporting the interests of the American fishing industry and wanting to twist the British Lion's tail, many Republicans feared the ship seizures as part of a ploy to pressure the United States to enter a free-trade pact with Canada.  

In fact, Canadians (primarily) were promoting a proposal for such a commercial union during 1886 and 1887.  Under its terms, there would be no trade barriers between the United States and Canada, and the two countries would share an internal tax system and an external tariff system, with the profits of both to be allocated proportionally.  The movement quickly gained momentum in the province of Ontario, but a bill for commercial union introduced into the U.S. House never made it out of committee.

President Cleveland used the Retaliation Act as leverage in negotiations with Britain over the fisheries question.  In July 1887, a six-member joint commission was formed, which produced the Bayard-Chamberlain Treaty, signed on February 15, 1888.  The treaty established a joint commission to decide which Canadian waters would be open to American fishermen, with inlets over six-miles wide defined as open waters.  It allowed American fishermen to dock in Canadian water to purchase supplies and to transship their catch to the U.S. after buying a license.  If the U.S. Congress lifted the duty on Canadian fish, then the licenses would be free and American fishermen would gain other privileges.  

In the politically charged atmosphere of a presidential election year, the Republican Senate rejected the treaty.  President Cleveland played political hardball by calling the Retaliation Act too weak and calling for legislation to ban all Canadian goods from entering any American territory.  Congress refused, as the president foresaw, but his request allowed him to appear tough with Britain, while giving him an excuse not to enforce the Retaliation Act.  It also was a slap at New England Republicans, since New England railroads were the major transporter of Canadian goods.  The British put the terms of the Bayard-Chamberlain Treaty into effect unilaterally, but the issue would continue to vex British-American and Canadian-American relations in the future.