Aguilera messed the anthem up. She doesn't even know the words, or that she messed it up. And completely oversang it (like she always does).
And, to add to the first post, her career isn't going strong, at all. Her last studio album, "Burlesque", debuted and peaked at #18 without a single impacting any charts. Its movie of the same name also failed to make its budget.
Her last studio full-length album, "Bionic", debuted and peaked at #3 with her lowest opening sales throughout her career, and sold only around 250k copies in total. The album produced no hit single, with "Not Myself Tonight" not reaching 400k copies and tumble after its first digital week (well, actually first few days). She was also forced to cancel her tour.
Critical-wise, "Bionic" got trashed by critics and receive no award nominations. And her last Grammy was from 2006's "Ain't No Other Man" (which, by the mean time, was being sued for not paying its sampling fee).
Her last last album, "Keeps Gettin' Better: A Decade of Hits", debuted at #8 only and sold only around 400k copies in total. Its leading single also did poorly after its sales-debut.
Her last #1 album was from 2006, her last #1 single was from 2001, and was a collaboration with P!nk, Mya and Lil Kum. Her last Top 20 single was from 2008. Her last Gold or more single was from 2006. Her last album with legs was from 2002. Last tour was from 2006.
Her peers around the same time, Britney Spears, Beyonce (Destiny's Child), P!nk and Rihanna are doing very well. While some of those 'pop *****es' also faded, like Avril Lavigne, and pop-jazzer Norah Jones.
Personally, she's divorced from her husband last year, and got arrested for being drunk in public places. She also falls into a lot of comparisons to Madonna, Lady GaGa, Whitney Houston, Mariah Carey, Britney Spears throughout the years, making her a 'second-best' to many. Her recent 'good' news are only 1.She performed a tribute for Aretha Franklin on the Grammy's, but she nearly fell on the stage; 2.She was chosen to be a judge on "The Voice", but it was not exactly the biggest show, not to mention the competition from "X-Factor" and "American Idol". Plus, basically only 'has-been' would became judges on a singing contest. Like Paula, like Kara, like Randy, like Brandy. There has only been one successful example of a judge becoming successful again and it is Jennifer Lopez which has just released ONE single thus far and is not really having radio success as of now. It's also notible to note that AI is the #1 TV show for the past decade, so...