“Contact your Republican senator,” Senator Chuck Schumer, the Senate minority leader, said in a speech before the vote. “See who votes for net neutrality and who votes against. And let them know how you feel about the way they voted.”

For Democrats, net neutrality is part of a three-legged stool — internet access, gun control and marijuana legalization — they are leaning on to entice young voters to engage in the midterm elections. Such voters broadly side with Democrats, even though they are notoriously complacent in nonpresidential election years.

“So the Democratic position is very simple: Let’s treat the internet like the public good that it is,” Mr. Schumer said.

It is unclear if net neutrality still holds the same interest that set off nationwide protests last December when the F.C.C., led by chairman Ajit Pai, a President Trump appointee, dismantled the rules. Tech companies and consumers decried the commission’s action as a major reshaping of the internet, because it would allow broadband providers to create fast lanes for websites that pay to make sure their content, like streaming video, gets priority delivery. Few changes to internet service are expected to come right away.

But it is not stopping Democrats from trying to use it to their advantage. They have been making a similar push on gun control, an issue that grabbed the attention of young people after a gunman slaughtered 17 students and staff members at Florida’s Marjory Stoneman Douglas High School in February. And Mr. Schumer has plans to introduce a bill next month that would legalize marijuana.