In this March 11, 2013 file photo, a sign reading "Stop the Transcanada Pipeline" stands in a field near Bradshaw, Neb., along the Keystone XL pipeline route through the state. With the clock ticking, supporters of a Senate bill to approve the Keystone XL pipeline are still scrambling to find the last vote.

Defying GOP, Obama vetoes Keystone XL pipeline bill

Republicans may try to override the veto, but have yet to show they can muster the 2/3 majority in both chambers of Congress that they would…