The Canadian government would have to play a significant role in any project to build new oil pipelines in Canada to overcome regulatory, financial and political hurdles and activist opposition, industry experts said. With U.S. President Donald Trump threatening tariffs on Canadian oil exports, several Canadian politicians have called for new pipelines to coastal export terminals to reduce dependency on the U.S. market. Oil is the most valuable export of Canada, which is the world's fourth-largest oil exporter, pumping 4 million barrels per day (bpd) over the border to U.S. refiners.