The unlikely marriage of music and politics goes back to George Washington's presidential campaign, when his supporters sang different ditties praising him to the tune of "God Save the Queen."

The songs a candidate chooses to feature during a rally or convention bring "an artistic expression to a vision and value of a movement," said 2016 Democratic National Convention CEO Leah Daughtry. "It's a deeply felt, hard-centered way to connect people emotionally to all the verbiage that is going on."

So next week's DNC will feature performance artists including Alicia Keys, Lady Gaga, Lenny Kravitz, Snoop Dogg, and Idina Menzel. The messages transmitted by those choices include the power of diversity, acceptance of differences in others, and perhaps a lingering love of "Frozen."

Meanwhile at the Republican National Convention in Cleveland, featured performers include Lynyrd Skynyrd, The Band Perry, The Marshall Tucker Band, various performers from "American Idol" and "The Voice," and Super Diamond, a Neil Diamond tribute band fronted by Rick Springfield. (Remember when Democrat Michael Dukakis used Diamond's "Coming to America" as a theme song in 1988?)

Kid Rock — who fully supported GOP candidate Mitt Romney using his song "Born Free" as a theme and even performed it live during the campaign — will perform on the final night of the RNC. (Rock — or Kid or Kid Rock. It's unclear which is correct on second reference — told Rolling Stone that he was "digging Trump.")

The messages transmitted by those choices are a little more nebulous. But the bottom line is music matters.

Hitting the right (and wrong) notes

Darrell West, vice president of governance studies and director of the Center for Technology Innovation at the Brookings Institution, said music is a major part of contemporary political campaigns.

"It's important to use music to reach out to voters," he said. "Music can highlight certain themes, like a longing for a time when the economy was better."

Which calls into question the themes past candidates have sought to highlight with their musical choices. In 1992, billionaire independent candidate H. Ross Perot frequently played Patsy Cline's 1961 "Crazy" during rallies, sometimes dancing with his wife on stage to the tune.

In 2008, GOP candidate John McCain, an out and proud Abba fan, said he wanted to use the band's 1977 hit "Take a Chance on Me" as his campaign song. He couldn't do so due to licensing fees, but perhaps that was for the best: How appealing is a president who is second choice? The song opens, "If you change your mind, I'm in the first in line. Baby, I'm still free. Take a chance on me."

In advance of the RNC, the Rock and Roll Hall of Fame unveiled "Larger Than Words: Rock, Power & Politics," a new exhibit built around music and politics. The show will run until Nov. 27. It will then move to the Newseum in Washington, D.C., opening Jan. 13, 2017, just in time for the presidential inauguration.

Rocking the vote

Greg Harris, the Hall's CEO and president, said certain genres of music — including folk and blues — have always "given voice to the voiceless and served as an easy way to convey messages for those who don't have a megaphone."

"Rock and roll has frequently been a prism that reflects what's happening in politics and culture," he said. "It can also be a force for change. Both sides of the aisle see the intersection of rock and politics."

Some artist do more than lend their songs. They lend themselves. Stevie Wonder sang "Signed, Sealed, Delivered, I'm Yours" at the DNC in 2008, an endorsement of candidate Barack Obama and his previous use of the song during his campaign. Lee Greenwood, who wrote the patriotic anthem "God Bless the U.S.A" has performed his song in support of multiple GOP candidates, including Ronald Reagan, Mitt Romney, and most recently Florida senator and failed 2016 candidate Marco Rubio.

West said it's not clear if a celebrity endorsement — via use of a song or an appearance at an event — has any impact on political outcomes.

"Candidates always want to have celebrity endorsements, because if a group is really big, like when Bruce Springsteen campaigned on behalf of Obama in 2012, that attracts a lot of publicity to the campaign," he said. "But I'm not sure if those endorsements sway any voters."

It's also unclear if a celebrity's request that a politician not use a song has impact, but if it does, GOP presidential candidate Donald Trump may have some trouble ahead. Since Trump began campaigning last summer, at least six singers or bands have asked that he stop playing their songs during rallies. Recently members of Queen were upset by Trump's rock star-like entrance to "We are the Champions" this week.

Neil Young, Adele, the Rolling Stones, and REM complained because they felt Trump's politics were contrary to their own, with Michael Stipe saying via Twitter, "Do not use our music or my voice for your moronic charade of a campaign." Steven Tyler of Aerosmith's gripe was a little different: in an October 2015 op-ed for the Huffington Post, he said he expected Trump to pay for the privilege of playing "Dream On."

A powerful song can give listeners the chills and become a permanent memory. When Harris thinks about political moments made more meaningful because of music, he goes to the 1969 anti-war demonstration in D.C. during which Pete Seeger led hundreds of thousands singing John Lennon's "Give Peace a Chance." Seeger didn't even like the song, Harris said.

"It's a pretty powerful moment when it goes from being a song to becoming a movement," Harris said.

Daughtry, who was CEO of the 2008 DNC, talks with awe about hearing Jennifer Hudson sing the "National Anthem" to open the final day of programming.

"We were in an 80,000 seat arena and her voice was bigger than life. I felt like she was standing right next to me," Daughtry said. "I remember stopping in the concourse and just being moved by the power."