When Americans took off the Fourth of July holiday to celebrate the country’s independence from the British, Paula Kerger, the chief executive of PBS, was busy fighting her own political battle.

As a deadline was fast approaching for Congress to decide whether to strip more than $500 million a year from public media, Ms. Kerger was promoting a campaign to save that funding, featuring celebrities like Bill Nye, Kerry Washington and Reba McEntire.

“We were really taking advantage of this moment, when people were talking about our country, to be part of that dialogue because that is what PBS is,” Ms. Kerger said. “We are very much a part of the fabric of America.”

Congress is expected to vote on that proposal, known as a rescission request, by the end of the week. If approved, it would end federal support for the Corporation for Public Broadcasting, which distributes money to NPR, PBS and local stations. That deadline has led to a rush of last-minute appeals from dozens of public radio and TV executives across the country, from Washington, D.C., to Anchorage.

“It’s really important,” said Ed Ulman, chief executive of Alaska Public Media, the largest PBS and NPR organization in that state, where some organizations are in danger of shutting down if the vote passes. “Everybody is reaching out to their senators and ensuring that this issue is front of mind,” he added.