“People are trapped with each other at home and can’t walk away,” said Emily Van Duyn, a postdoctoral fellow at Stanford University’s Program on Democracy and the Internet who is studying how the pandemic is affecting couples with clashing political views. “Before, the answer was to withdraw completely, and now they can’t.”

The greatest tension, she said, comes over what news to watch on TV, particularly in families where the choice is between MSNBC and Fox.

One Fox viewer she interviewed recently complained that his girlfriend was being “brainwashed” by MSNBC, a longtime target of the right, with its frequent Trump-hating commentary.

“It’s a huge dividing thing,” Dr. Van Duyn said. “People say, ‘I can’t watch this with you, and I have to go to the other room.’”