Oh yeah! The Union had enough troubles winning without adding Britain as an enemy. The fact that the South could and did send troublesome persons into the North via Canada was enough trouble. The 21 Confederate cavalrymen who raided St. Albans, Vermont on October 19, 1864:

The raiders fled with the money [$208,000] into Canada, where they were arrested by authorities. A Canadian court decided that the soldiers were under military orders and that the officially neutral Canada could not extradite them to the United States. The Canadian court's ruling that the soldiers were legitimate military belligerents and not criminals, as argued by American authorities, has been interpreted as a tacit British recognition of the Confederate States of America. The raiders were freed, but the $88,000 the raiders had on their person was returned to Vermont.