Washington (CNN) -- The fate of the controversial Keystone pipeline wasn't the only thing at stake during a crucial vote in the Senate on Tuesday. The vote blocking legislation that would have authorized the pipeline's construction previews a new era of animosity between resurgent Republicans in Congress and President Barack Obama. It could also seal the fate of embattled Democratic Sen. Mary Landrieu of Louisiana, who had made pushing the measure a focal point in an uphill battle to fend off a GOP challenger in a runoff election next month. Landrieu fell one vote short of securing the support necessary to advance the legislation. All 45 Republicans voted for the measure and 14 Democrats did, too. But she needed one more Democrat to join her to reach the critical 60 vote threshold.

In her speech, Landrieu made an aggressive case in favor of approving the pipeline while other

OPTIONS:
- Barack Obama dissented.
- CNN dissented.
- Congress dissented.
- Democrat dissented.
- Democratic dissented.
- Democrats dissented.
- GOP dissented.
- Keystone dissented.
- Landrieu dissented.
- Louisiana dissented.
- Mary Landrieu dissented.
- Republicans dissented.
- Senate dissented.
- Washington dissented.


Democrats dissented.