Democrats argue that the debate largely ceased to be about the pipeline itself after Republicans demanded as part of last month's payroll tax cut package that Obama make a decision on the project by late February. Even though Obama seemed to be leaning in its favor, he had said earlier that he needed more time to evaluate the environmental and health consequences. And so, his administration argued, the GOP essentially forced him to turn down the application from TransCanada.
Republicans seemed all too aware of this possibility. "It's a question of whether we'd rather have the pipeline or the issue," a GOP aide said in December. They chose the issue, bringing into question how much they care about the pipeline itself. Indeed, not forcing a decision would have neutralized the politics surrounding the matter.
But now Republicans have turned it into a weapon, and the politics are win-win for them. Their base overwhelmingly supports the pipeline and its capacity for some temporary job creation puts them on the right side of the most important issue on voters' minds in this election year.
For Democrats, the issue is a headache because their constituencies are split: environmentalists oppose it, while labor and big business have forged an unlikely alliance in its favor. The GOP push may not yield anything substantive, but it forces Obama to keep taking sides within his base, and answer to Republican attacks that he's blocking a job creation opportunity.
That's why Republicans want to keep the Keystone issue atop the agenda for as long as possible.