Presidential Campaigns See Texting as a Clear Path to Voters

In those campaign cycles, political text messages could seem more jarring.

“A text is almost a sacred thing,” said Vincent Harris, the digital director for Mr. Paul’s campaign. “This space is reserved for your closest friends, your family, people who know you well enough to have your number and bypass a voice mail or email. I think it’s taken several years for the electorate to warm up to this.”

Mr. Harris recalled a “largely unsuccessful” texting campaign for Bob McDonnell during his winning race for governor of Virginia in 2009, when voters refused to surrender their cellphone numbers even after they were offered free tickets to a Washington Redskins game.

But since then, as social-media use has exploded, people’s attitudes toward text messages have shifted. Now that they routinely accept interruptions on their cellphones for traffic and weather alerts, Uber pickups, restaurant reservations and hair-salon appointment reminders, they are just as likely to welcome hearing from someone they want to see in the White House.