I don’t recall him threatening to veto Landrieu’s bill for Keystone if it passed. Of course, she’s Dim and was getting beaten in her re-election.
Mitch McConnell blasts White House veto threat over Keystone bill — saying none threatened over Mary Landrieu’s identical 2014 bill
http://www.nola.com/politics/index.ssf/2015/01/senate_majority_leader_mcconne.html
January 06, 2015