WASHINGTON — The governor of Nebraska on Tuesday approved a revised route through the state for the Keystone XL pipeline, setting up a decision for President Obama that pipeline opponents say will be a crucial test of his intentions on climate change.

Gov. Dave Heineman, reversing an earlier position and brushing aside vocal opposition from some citizen groups, said the pipeline could be built and operated safely and would bring thousands of jobs and hundreds of millions of dollars in new revenue to Nebraska.

The decision came a day after Mr. Obama made an assertive pledge in his Inaugural Address to tackle climate change in his second term. Opponents of the pipeline, which would carry heavy crude oil from tar sands formations in Alberta to refineries on the Gulf Coast, say that the extraction and consumption of the oil would significantly worsen global warming and perpetuate the nation’s dependence on dirty fossil fuels.

Mr. Heineman, a Republican, said in a letter to Mr. Obama and Secretary of State Hillary Rodham Clinton that his state had found in its review that the new route avoided sensitive lands and aquifers. Mr. Obama rejected the previous route last January on the grounds that construction of the pipeline threatened Nebraska’s Sand Hills region and that a spill could contaminate the critical Ogallala Aquifer.