So far there have been no mass encampments on the Nebraska prairie, no tense standoffs with the police, no highway blockades. But Jane Kleeb, a leader of the pipeline opposition, said the more muted tactics in Nebraska should not be mistaken for a lack of organization or tepid sentiments.

Opponents here managed to delay Keystone XL for years during the Obama administration, challenging state permitting rules and drawing national attention to the pipeline. They have fought with lawsuits and testified about legislation. Here on the Harrington farm, activists built a small solar- and wind-powered barn on the side of a dirt highway, right along the proposed path of Keystone XL. They see it as both a physical barrier to construction and a blunt statement about clean energy.

Some supporters of the pipeline acknowledge the concerns of opponents, but say the pipeline will be safe — and economically beneficial.

“I think the state is ready to move on from this issue,” said Jamie Karl, a vice president of the Nebraska Chamber of Commerce and Industry, which for years has supported the pipeline.

“I think this project shines the light on the fact there’s a large disconnect between energy production and the average American,” said Mr. Karl, whose family owns land not far from a different oil pipeline. “Yes, we all want no risk when it comes to energy production. We understand that. But gas doesn’t magically appear in your car tank. Asphalt doesn’t magically appear on the road you drive on.”

Still, if construction ever begins, opponents say they are willing to participate in civil disobedience. But opponents in Nebraska are betting that they can block the pipeline through other means. The State Public Service Commission, which will decide as early as mid-September whether to grant a permit for Keystone XL, will hold five days of hearings on the project in August.

“I am hopeful,” said Jenni Harrington, one of four sisters who grew up on this farm along the southern portion of the proposed route. “I think people in Nebraska aren’t just pushovers.”