Some rock stars should not dabble in politics.

Take Madonna.

WASHINGTON, DC - September 23rd, 2012 - Music icon Madonna performs at the Verizon Center as part of the MDNA Tour. (Kyle Gustafson/FOR THE WASHINGTON POST)

On Monday night at a concert in Washington, the ‘80s icon offered an onstage lecture about politics where she mentioned Abraham Lincoln and Martin Luther King, Jr. She said, “Those kind human beings did not die for nothing! They fought for our freedoms! So y’all better vote for [expletive] Obama, okay?”

Then she said a doozy: “For better or for worse, all right, we have a black Muslim in the White House, okay?”

The Obama campaign surely cringed. Was Madonna simply being ironic? Or does she really think Obama is a Muslim? The Post’s Reliable Source column tried to reach Madonna’s rep but to no avail. In the same show, Madonna stripped off her shirt and shimmied down her pants. Voila! The word “OBAMA” was written across her lower back – a political tramp stamp.

“When Obama is in the White House for a second term I'll take it all off,” she said.

The audience whistled.

“Muslim” and “Obama” are two words that probably shouldn’t be connected in this election season even tongue-in-cheek by Madonna. If that is, indeed, how she meant it. The tea party and birthers will surely seize on her statement, creating a viral headache – and headlines – for Obama.

Rocks stars are voters, too, but before they go off with a half-cocked opinion, maybe they should have a prepared, rehearsed statement. Rule one: Do no harm. Madonna is a role model for Obama’s natural base: voters under 45 and the GLBT crowd. Sure, Madonna, be passionate, get out the vote but don’t hurt your candidate.

Celebrity endorsements can help candidates many times. They can persuade a fan base to donate money, work for the candidate and spread the message. Obama’s connection to Jay-Z and Beyonce go a long way with the millennial generation.

Oprah’s endorsement of Obama in 2008 helped to woo a lot of soccer moms, who may have leaned toward Sarah Palin, into the voting booth for the Democratic ticket. Duran Duran’s John Taylor, a Brit who can’t even vote in the United States, has come out in favor of Obama, and Generation X women listen.

Rock gods can certainly use their influence and platform for political statements. Guns N’ Roses Duff McKagan wrote in July that Obama should get the troops out of Afghanistan. Lady Gaga often uses her celebrity to shed light on bullying, gay rights and, now with her recent weight gain getting much attention, eating disorders.

But sometimes a celebrity connection does more harm than good to a politician. Two words: Clint Eastwood.

Rapper Nicki Minaj created waves a few weeks ago when she declared her endorsement of Republican nominee Mitt Romney via verse. “I’m a Republican voting for Mitt Romney. You lazy b—-es is f—ing up the economy,” she said in a song on Lil Wayne’s new mixtape “Dedication 4.”

But, see, Minaj was joking. We think.

Minaj tweeted earlier this month, “Ha! Thank you for understanding my creative humor & sarcasm Mr. President, the smart ones always do... *sends love & support* @BarackObama.”

To that, Obama said in a radio interview, “I’m not sure that’s actually what happened [her Romney endorsement]. I think she had a song on there, that – a little rap that said that. But she likes to play different characters.”

Madonna's controversial statements used to be about purposely pushing the envelope from sexuality to women's rights. By linking the word "Muslim" to Obama, she is, unwittingly or not, amplifying the message of those on the far, far right. Politics is a minefield. Madonna should stick with safe topics like sex and dancing.

Suzi Parker is an Arkansas-based political and cultural journalist and author of “Sex in the South: Unbuckling the Bible Belt.” Follow her on Twitter at @SuziParker