Why are singers always screwing up the national anthem? Is it that hard?

Steven Tyler.

Last week Aerosmith front man Steven Tyler came under fire for his rendition of "The Star Spangled Banner" ahead of the AFC championship game between the Baltimore Ravens and the New England Patriots.

The rock legend was widely panned for his failure to hit the high notes, and he also had some trouble with the lyrics. But the complaints were nothing new, and perhaps for good reason. Recording artist Erica Chase tells Pop Tarts that, in characterizing our country's national anthem, “difficult would be an understatement.”

“The song itself does contain many challenging intervals and goes from lower to upper register frequently and has more than one climax to it,” she said. “A lot of stars are used to performing in their niche and along with a band or group, so this is completely out of their comfort zone.”

A lot of stars indeed.

At last year’s Super Bowl, Christina Aguilera forgot one of the lines and ended up singing the same phrase twice after “getting lost in the moment and forgetting her place.” 80s sensation Cyndi Lauper muffed the words during her performance at the 2011 US Open, which happened just after a moment of silence for the victims of 9/11. “Idol” runner-up Lauren Alaina flubbed a lyric and fell silent ahead of the Detroit Lions-Green Bay Packers game last Thanksgiving.

And those are the "good" mess-ups.

Michael Bolton forgot the words during the 2003 Red Sox versus the Yankees American League Championship game, prompting him to turn to his hand for written notes. Track star Carl Lewis promised to “make it up” to his upset audience halfway through a 1993 anthem performance. And Roseanne Barr infamously gave a shrill, off-pitch rendition of the anthem at a National League baseball doubleheader, topped off by a crude on-field gesture.

POLL: Should celebs sing the national anthem?

“The national anthem is an incredibly challenging song to sing. It feels easy, because it’s so familiar, but it has a one and a half octave range, which means you have to have strong vocal control in order to really do it justice," M. Tye Comer, editor Billboard.com told Pop Tarts. "It’s one of the hardest songs for non-professional singers to execute, but it’s brought a lot of seasoned vocalists to their knees as well."

“A lot of artists have the tendency to over-sing it, which often leads to missed notes in the heat of the moment," Comer said. "Couple that with the fact that potentially millions of people are hearing them perform a song that everyone from grandparents to toddlers are familiar with – it’s easy for the nerves to take over.”

But not everyone is so understanding, Franklin Rodriguez, (a.k.a. El Medico) an audio engineering instructor at the Miami campus of SAE Institute, a school for creative media technologies, argues that the song itself isn’t that challenging, and that the frequent flubs have more to do with stars’ unfamiliarity with the lyrics.

“Artists sometimes mess up the anthem because it is not a song that they spend a lot of time rehearsing and/or performing, and is more of a one shot thing," he reasoned. "Also most pop songs have a lot of repeating parts, meaning less words to remember, and the anthem doesn’t, so they have to memorize the words more than usual. Singers also usually use ‘cues’ within the music to remind themselves of where they should be in a song. Since the anthem is usually performed acapella, it is a lot easier to get lost or forget some words.”

So, in the wake of 'Idol' judge Steven Tyler’s anthem, chances are 'Idol' champion Kelly Clarkson is working overtime to ensure she enjoys smooth sailing with her rendition at Sunday’s New York Giants/New England Patriots match up.

“Kelly is a talented singer and she definitely has the chops to pull it off. If she can keep her grace under the pressure, the Super Bowl could be a real star moment for her,” Comer said.

The stream of star-studded Star Spangled Banner botches can also serve as a reminder that perhaps we could all do with a little polishing.

“A big thing is that at some level, we all think we know the words to the anthem, but most of us don’t,” Rodriguez added. “Most people know two or three lines, and the best we can muster is a bunch of mumbles thereafter.”

For those stars who wonder how the national anthem should be sung, we bring you the incomparable Robert Merrill...