It may be a milestone in a long debate — but it's not the end of the years-long saga, which involves plans to build a new oil pipeline from Alberta and connect it to an already-functioning portion in the southern U.S. Here are five facts about the status of the Keystone XL project:
—This was the undercard — now the main event: A veto comes as no surprise. The White House repeatedly said it would stop lawmakers if they tried forcing an outcome on Keystone XL.
The White House says it's the president who decides what pipelines cross the border, not Congress, and past court decisions bear that out. That responsibility was most recently laid out in Executive Order 13337, signed by George W. Bush in 2004.
—So when is the main decision? Soon — maybe: The regulatory process is in its final phase. The State Department has finished collecting input and is now preparing a recommendation to the president. Obama must then decide whether the project is in the U.S. national interest.
When Obama talks about Keystone XL, he plays down its potential for jobs and lower U.S. gas prices. Instead, he says, the decision will be based on climate change. The latest State Department review says it won't increase emissions, but another U.S. federal agency has questioned that conclusion.
As for the timing? "I don't have any prediction of the timeline for you," a State Department spokesman said this month.
—Try, try again: Congress will probably produce more Keystone XL bills. And they could be more tempting for the president to sign.
Lawmakers have already hinted at creative legislative strategies. One predicted that a pipeline clause would be added to a massive infrastructure bill — an issue on which the president is keen to make progress.
Some members will only approve new infrastructure spending if it doesn't drive up the deficit, so both parties are working on a solution: update the U.S. tax code, encourage companies to bring home profits currently sheltered overseas, have that cash pay for new roads and bridges in an infrastructure bill, and toss a certain Canadian oil pipeline into that legislative mix.
—Meanwhile, in Nebraska: Keystone's Waterloo — where the project first faced opposition, and then multiple court fights.
The latest legal battle has just begun. Some predict this development could delay construction in the state for another 18 months. In the face of legal pressure, the pipeline company, TransCanada Corp., has stopped trying to use eminent-domain power to force resistant landowners to allow the pipe on their property. It's now agreed to let courts settle the matter.
These kinds of delays and disputes have driven up the cost of the project by nearly half, to $8 billion.
—Presidential vetoes — get used to them. Obama has only vetoed two bills throughout his presidency — fewer than any predecessor in more than 120 years. He had allies in Congress blocking bills for him.
That's now changed. Democrats have lost control in both chambers of Congress, so they can't run interference as easily. Obama has now signalled he'll use his veto power by scrapping Senate Bill No. 1 — the Keystone XL legislation, the first bill Republicans introduced in the new Congress.