Each gov. has its own agenda some things both will agee on but others perhaps not. Right now US is getting heavy Canadian crude at up to 20% discount and perhaps Washington likes to keep it that way for a while.
President has his green/environment supporters who he may wish to support. on the other hand easier source of non middle east crude has its benefits eg in supply disruption. Perhaps the biggest driver will be the Canadians plan to build pipelines to their coasts and ship out crude to foreign markets, probably with long term supply agreements and that could limit some of the future crude that could come to the US, not an issue right now but in 10 years and longer important. Of course there is the issue of good paying construction jobs for the keystone one of the biggest north american construction jobs ever. It is easy for president Obama to leave the okay decision to the next administration. so its not a done deal perhaps 70% chance of approvalÉ
I actually think the decision will be made by national security types who Obama seems to listen to. Not to protect yourself from an oil collapse in the Middle East is insane. I would go so far to say if he does not approve Keystone he is a traitor and should be impeached.