Katy Perry and Usher rock for military kids at inaugural concert

As dignitaries, donors and deal makers flooded into Washington, D.C. for the second inauguration of President Barack Obama, his wife headlined an event that boasted its own considerable star power, while transcending the partisan warfare that has engulfed the city.

In the main, cavernous room of the Washington Convention Center, First Lady Michelle Obama and the Second Lady, Dr. Jill Biden, hosted the Kids' Inaugural Concert, thrown for and in honor of the children of military families nationwide.

The event was officially emceed by "America's Got Talent" host Nick Cannon, who stood in front of four massive screens stretching the horizontal length of the ballroom, drenched with projection-illuminated stars and set with light blue columns that suggest the capital is a friendly place worthy of the grandeur described in the kids' textbooks.

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Usher led off the concert with a string of his biggest hits. Perhaps because he has earned universal awareness among elementary school students through his mentorship of Justin Bieber, the Grammy-winner was greeted by dancing children of all ages; there were four-year-olds standing on their chairs, humming along and bending their knees, often holding hands with their mothers.

Like many that followed, Usher gave a pep talk about the importance of youth activism, and the value of the sacrifices that military children make; it was a seemingly sincere tribute, and was repeated through video messages from stars such as those from Disney Channel's "Shake It Up"; Nickelodeon's "Big Time Rush"; the hit boy band The Wanted; Jimmy Fallon (who deadpanned and called himself One Direction's Harry Styles); Ellen DeGeneres (who drew massive cheers); and David Letterman, whose smiling words were met with absolute confused silence, an ironic highlight for any adult in the room.

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Several cast members from "Glee" -- Darren Criss, Naya Rivera and Amber Riley -- earned their own raucous cheers, as they performed an acoustic song each. Riley's rendition of Christina Aguilera's "Beautiful" was a particular hit.

Among the more notable details: the concession stand in the back -- more like just a few food carts -- carried both fresh fruit and ice cream. For a first lady that has promoted healthy eating among children, it was a compromise in a special celebratory occasion.

Obama and Biden took the stage near the end, calling in groups of military kids on video chats broadcast on the big screens. The first lady in particular was earnest in her words, appealing to all ages.

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"You see, when we said we wanted to host a concert to honor our military kids, let me tell you, everyone wanted to be here. Usher wanted to be here," she said. "Katy Perry wanted to be here. Nick Cannon, the folks from 'Glee,' and all the other amazing performers -- they wanted to be here, too. And let me tell you, they’re not here for me. They’re not here for Dr. Biden. They are here for all of you. Because they know the kind of sacrifices that you all make every single day."

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Soon after, Perry took the stage, in her trademark Uncle Sam-style corset, with a full band and backup singers behind her. She sang for songs -- "Teenage Dream," "Part of Me," "Wide Awake" and "Firework," the last of which was played in front of a photo montage of President Obama with children -- gave the one semi-political moment of the night, celebrating "four more years" of Obama and Vice President Joe Biden.

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