It’s partly innoculation to insulate Cassidy and present him as out front and acting as a leader on this.
Partly it’s setting up Keystone as veto bait for Obama. He signs it, and more of the LA environmentalists will stay home and he eats long-term anger by the national enviros.
He vetoes it and Cassidy starts running ads about sending Obama a message by sending Mary home.
Rock/hard place situation for Mary.
I think Cassidy should be very vocal that he wants a vote, now! That it is the right thing to do and it shouldn’t have taken Landrieu so long to do it, but better late than never.
Landrieu’s situation only gets worse if there is a vote, and even worse if it passes and is vetoed.