Relying on Canadian crude imports is the best choice for the United States – not just because it’s reliable and secure but because of Canada’s unmatched environmental record, Natural Resources Minister Joe Oliver said Tuesday.

Adding green to the attributes of Alberta’s oil sands is the latest twist in Ottawa’s concerted effort to push for U.S. approval of the controversial Keystone XL pipeline designed to funnel more than 800,000 barrels a day of Canadian crude to Texas Gulf oil refineries next to deep-water export terminals.