Mr. Ryan is not a politician one readily associates with the Zoomers of TikTok. His talking points tend to revolve around issues like reviving American manufacturing rather than, say, defunding the police. But the chino-clad congressman wasn’t naïve to the nontraditional places from which political influence might flow. Years ago he was all in on meditation. Why not try the social platform of the moment?

His teenage daughter, Bella, got him up to speed and taught him some of the dances that had gone viral on the app. “I just thought it was hysterical, and that it was something really cool that her and I could do together,” Mr. Ryan said in a phone interview.

Soon enough, he was posting on his own account, sharing video montages of his floor speeches and his views on infrastructure legislation, backed by the sound of Taylor Swift’s “All Too Well.” (As any TikTok newbie would quickly learn, popular songs help videos get discovered on the platform.)

“I started to see it as an opportunity to really speak to an audience that wasn’t watching political talk shows or watching the news,” Mr. Ryan said. This year, he’s running for Ohio’s open Senate seat; he thinks TikTok could be a crucial part of the race.

But as primaries begin for the midterm elections, the real question is: What do voters think?

Privacy, Protest and Punditry

Social media has played a role in political campaigning since at least 2007, when Barack Obama, then an Illinois senator, registered his first official Twitter handle. Since then, enormous numbers of political bids have harnessed the power of social platforms, through dramatic announcement videos on YouTube, Twitter debates, Reddit A.M.A.s, fireside chats on Instagram Live and more. TikTok, with its young-skewing active global user base of one billion, would seem a natural next frontier.

So far, though, compared with other platforms, it has been embraced by relatively few politicians. Their videos run the gamut of cringey — say, normie dads bopping along to viral audio clips — to genuinely connecting with people.

“TikTok is still in the novelty phase in terms of social media networks for political candidates,” said Eric Wilson, a Republican political technologist.

Republicans in particular have expressed concerns about the app’s parent company, ByteDance, whose headquarters are in China. In the final year of his presidency, Donald J. Trump signed an executive order to ban the app in the United States, citing concerns that user data could be retrieved by the Chinese government. (President Biden revoked the order last summer.)

After a brief stint on the app, Senator Marco Rubio of Florida, a Republican, deleted his account. He has since called on President Biden to block the platform entirely. In an email statement, Mr. Rubio, 50, wrote that TikTok “poses a serious threat to U.S. national security and Americans’ — especially children’s — personal privacy.”

That point has been disputed by national security experts, who think the app would be a relatively inefficient way for Chinese agencies to obtain U.S. intelligence.

“They have better ways of getting it,” said Adam Segal, the director of the Digital and Cyberspace Policy program at the Council on Foreign Relations, among them “phishing emails, directed targeted attacks on the staff or the politicians themselves or buying data on the open market.”

Regardless, TikTok seems to have empowered a new generation to become more engaged with global issues, try on ideological identities and participate in the political process — even those not old enough to vote.

There have been rare but notable examples of TikTok inspiring political action. In 2020, young users encouraged people to register for a Tulsa, Okla., rally in support of former President Donald Trump as a prank to limit turnout. Ahead of the rally, Brad Parscale, Mr. Trump’s 2020 campaign manager, tweeted that there had been more than a million ticket requests, but only 6,200 tickets were scanned at the arena.

Such activity is not limited to young liberals on the platform. Ioana Literat, an associate professor of communication at Teachers College, Columbia University, who has studied young people and political expression on social media with Neta Kligler-Vilenchik of the Hebrew University of Jerusalem, pointed to the political “hype houses” that became popular on TikTok during the 2020 election. The owners of those accounts have livestreamed debates, debunked misinformation spreading on the app and discussed policy issues.

“Young political pundits on both sides of the ideological divide have been very successful in using TikTok to reach their respective audiences,” Ms. Literat said.

You’ve Got My Vote, Bestie

Many of the politicians active on TikTok are Democrats or left-leaning independents, including Senator Jon Ossoff of Georgia, Senator Bernie Sanders of Vermont, Senator Ed Markey of Massachusetts, Representative Ilhan Omar of Minnesota and the mayors of two of America’s largest cities, Lori Lightfoot and Eric Adams (who announced he had joined this week with a video that featured his morning smoothie regimen).

This could be because the platform has a large proportion of young users, according to internal company data and documents that were reviewed by The New York Times in 2020, and young people tend to lean liberal. (TikTok would not share current demographic data with The Times.)

“If you are a Democrat running for office, you’re trying to get young voters to go out and support you,” said Mr. Wilson, the Republican strategist. “That calculation is different for Republicans, where you’re trying to mobilize a different type of voter” — someone who is likely older and spends time on other platforms.

For his part, Mr. Markey has cultivated a following on TikTok with videos that are a mix of silly (such as him boiling pasta in acknowledgment of “Rigatoni Day”), serious (for example, him reintroducing the Green New Deal with Alexandria Ocasio-Cortez and Cori Bush) and seriously stylish (him stepping out in a bomber jacket and Nike high tops). The comments on his videos are filled with fans calling him “bestie” (“go bestie!!”, “i love you bestie,” “YES BESTIE!!!!”).

The feeling is mutual. “When I post on TikTok, it’s because I’m having fun online and talking with my friends about the things we all care about,” Mr. Markey, 75, wrote in an email. “I listen and learn from young people on TikTok. They are leading, they know what’s going on and they know where we are headed, especially online. I’m with them.”