Keystone is just one issue of licensing energy infrastructure. In reality it is more symbolic than substantial.
Obama can fold on Keystone and it would change very little. The real problem is the power of the regulatory bureaucracy and their collusion with business interests intent on limiting competition or obtaining federal funding, or making money indirectly through the regulatory process - the mass of “consulting” firms.
There are 1000x more blocked infrastructure projects or imminent opportunities for them than Keystone.
Symbolic and political. Keystone is a wedge issue. It forces the vulnerable or "moderate" Democrat to make a choice between political survival or Barack Obama.
The decision will be in the head of B. Hussein Obama. He and his band of intellectual idiots will look upon these Democrats as turncoats when they vote for Keystone. He will see his once solid coalition crumble.
Make them decide.