The divisive Keystone XL pipeline project got a big boost when the US House of Representatives passed a bill last week approving its construction. The Senate is expected to soon follow suit, putting renewed pressure on the White House to drop its opposition to the 1897 km transnational pipeline bringing 800 000 thousand barrels of Canadian tar sand oil per day to refineries near the Gulf of Mexico.

The bill is controversial because tar sand oil is said to be more polluting than other types of oil. The litmus test, according to President Obama, is whether or not the project will contribute to global warming. If current governmental studies suggest that it would then Mr. Obama will likely use his veto to doom the project. Both houses of congress do not have sufficient votes among them to override a presidential veto.