NASHVILLE — Last Sunday night, Taylor Swift did something she had never done in her stratospheric career as a pop star: She endorsed a political candidate in Tennessee, her adopted home state.

She endorsed two candidates, actually, both Democrats: Representative Jim Cooper, who is running for re-election to Congress, and former Gov. Phil Bredesen, who is running to fill the Senate seat that the Republican Bob Corker is voluntarily, sort of, vacating.

Swift did more than simply endorse the Democrats. In an Instagram post to her 112 million followers, she also slammed Marsha Blackburn, the Republican House member running against Mr. Bredesen: “Her voting record in Congress appalls and terrifies me,” Ms. Swift wrote. “She voted against equal pay for women. She voted against the reauthorization of the Violence Against Women Act, which attempts to protect women from domestic violence, stalking and date rape. She believes businesses have a right to refuse service to gay couples. She also believes they should not have the right to marry. These are not MY Tennessee values.”

There’s a good reason for any female artist, especially one who got her start on country radio, to think twice about wading into politics. To understand how much courage it took for Taylor Swift to post such a statement, you need to remember what happened to the Dixie Chicks back in 2003. At the time they were one of the most popular acts in country-music history and the top-selling female group of all time. Then, in the run-up to the Iraq war, the lead singer, Natalie Maines, told a London audience that the group opposed the coming invasion: “We do not want this war, this violence,” she said, “and we’re ashamed that the president of the United States is from Texas.”