Lori Harman found the out-of-the-blue text message she received this week to be a little unnerving.

"This is President Trump. Your early vote has NOT been RECORDED on Indiana's roster. I need you to vote GOP. Confirm your polling place >> (link to the Republican National Committee website)"

"I was like 'whoa, why is President Trump texting me,'" the Indianapolis woman said. "I have no idea how they got my number. It was kind of shocking."

Text messages are the latest battlefield in the fight to capture voters' attention in 2018. They are cheaper and more effective than other forms of advertising, and one expert says they are here to stay.

Lawsuit:Indianapolis fired supervisor because of his Trump support and MAGA hat

Boo:These are some of the ghosts haunting the Indiana Statehouse

"People don't answer the phones like they used to, but they can't ignore a text," said Andrew Downs, a professor and the director of the Mike Downs Center for Indiana Politics at Indiana University-Purdue University Fort Wayne.

This year, text messages are fast becoming a reliable way for political candidates and parties to drum up support or get voters to the polls.

"Text messaging is to 2018 what Facebook and Twitter were to 2008 and 2012," said Pete Seat, director of strategic communications for the Indiana Republican Party.

Voters with a DVR can skip right past television ads, mailers get tossed in the trash, but Seat said almost 100 percent of text messages are being read.

"The engagement and open rates are through the roof," Seat said, noting the state and national GOP has been using text messages primarily as a way to get out the vote.

One problem, however, is that some of the messages are going to people who do not want them.

"They're sending this to people who are Democrats and it's a really bad idea," said Kate Sweeney Bell, chairwoman of the Marion County Democratic Party.

Bell said her office has been fielding numerous complaints from voters who have received unsolicited text messages.

Seat said the overwhelming majority of recipients appreciate the reminders, which direct them to information about how to find their polling place or where to cast an early ballot. Those who don't want the messages can easily opt out, Seat said.

Two recipients of the unwanted text messages replied "Stop" and received messages saying they had been unsubscribed.

IndyStar has emailed the Republican National Committee seeking comment.

Political parties have found a way to side-step the FCC's Telephone Consumer Protection Act ban on robocalls and robotexts to cell phones.

The parties use smart phone apps like Opn Sesame and Hustle to send peer-to-peer messages that fall just short of a robotext. The apps fill in phone numbers and messages, but a human user must press a button to actually send each text, one at a time.

"We're just doing everything we can to make sure voters are getting out there and voting," said J.D. Ford, a Democrat running against incumbent Republican Mike Delph for a seat on the Indiana State Senate.

Ford said he has been using the Hustle app to reach out to voters. He said he got the idea from Bernie Sanders, who used the text messaging app in his 2016 Democratic presidential primary run against Hillary Clinton.

"Occasionally we are going to get some who do not want to be reached in this manner," Ford said, "Overall, the response has been very positive."

Downs, the professor from Fort Wayne, said one exasperated Indiana voter called him recently asking how to get Donald Trump to stop sending text messages.

The parties generally get the names and phone numbers through public voter information. By going to the county clerk's offices, campaigns and parties can see who has voted in prior Democratic or Republican primaries, and who has not yet cast an early ballot.

To get Trump to stop texting, Downs told the man he should vote so the campaign knows to stop bothering him.

"You can delete them very quickly, you can get mad about it, but it's a form of voter contact," Downs said.

"It's going to get used, and some would say overused and misused as well."

Call IndyStar reporter Vic Ryckaert at 317-444-2701. Follow him on Twitter: @VicRyc.