 Advocates of Laurier's plan argued that north–south trade made more economic sense than trying to trade across the vast, empty prairies, using a CPR which was already provoking resentment for what were seen as high freight rates.Macdonald was willing to see some reciprocity with the United States, but was reluctant to lower many tariffs.American advocates of what they dubbed "commercial union" saw it as a prelude to political union, and did not scruple to say so, causing additional controversy in Canada.