Eva Longoria strode on stage at the Democratic National Convention tonight looking every bit the international star that she is. She didn’t have an empty chair, but she carried a sharp analysis and a disarming sass. She spoke of her modest upbringing in Texas and how, while college was not optional in her family, the money was sparse. Eva took what jobs she could—fast food, mechanics, aerobics—to pay for college and then pay back her loans. Her family believed that the opportunity America would offer if she got her degree was a worthy investment. Pivoting from the personal to the political, Eva drew a sharp line between the candidates with the thunderous applause line: “The Eva Longoria who worked at Wendy’s flipping burgers—she needed a tax break. But the Eva Longoria who works on movie sets does not.”

In the theater of modern conventions, party platforms are pro forma, but party pizzaz is paramount. This is the reason the Republicans were so thrilled to have a star like Clint Eastwood that they didn’t bother to vet his bizarre performance last week in Tampa. The Democratic National Convention is the final dress rehearsal for the last two months of the campaign, where they take the narrative for a spin and the audience response is like real-time market-testing. And Longoria was there to appeal directly to key target demographics and leave them feeling better about an administration that’s lost some luster in the long slog of the last four years.

Young people voted in record numbers in 2008. Even more, this is the group that gave the long-shot candidate a rock-star status that helped propel him from a long-shot candidate to the White House. But with their economic prospects dim because of the recession and payments due on college loans, their participation this cycle is far from assured.

Just under 60 percent of young voters say that they will definitely vote this fall, a twenty-point drop from this time four years ago. The president is leading Mitt Romney by a secure margin among the under-30 set, but still a significantly lower number than 2008. Being outspent three-to-one by outside groups, the Democrats need a high turnout election to secure the margin of victory. While there’s time for that to change, the campaign can’t afford to take any chances.

Hence, the final night of #DNC2012 was star-studded. Set between a national anthem by Marc Anthony and a set by the Foo Fighters, Mary J. Blige brought down the house with her cover of Bono’s “One Love.” In between, Eva was joined by actress Kerry Washington, who built on the story John Lewis told earlier in the evening.

“So many struggled so that all of us could have a voice in this great democracy and live up to the first three words of our constitution: We the people. I love that phrase so much. Throughout our country’s history, we’ve expanded the meaning of that phrase to include more and more of us.

Today there are people trying take away rights that our mothers, grandmothers and great-grandmothers fought for: our right to vote, our right to choose, affordable quality education, equal pay, access to healthcare. We the people can’t let that happen.”

Next up, Scarlett Johansson conjured an image of the magic of her first trip to the voting booth, reminiscing, “When I was a little girl, my mother—a registered Democrat—would take me into the polling booth, and tell me which buttons to press and when to pull the lever. Is that even legal? I remember the excitement I felt in that secret box, and feeling like my mom’s vote wasn’t just about the candidate, it was about our family—and all the families just like ours.” Scarlett seemed familiar with studies showing that a firm commitment to vote increases the likelihood of actually following through. She implored, “You know who I’m voting for. I’m not going to tell you who to vote for. I’m here to ask you to commit to vote.”

It wasn’t just the movie stars on parade tonight in Charlotte. Internet sensation and son of two lesbians, Zach Wahls spoke to the crowd about how much it meant to him to have a president who recognizes his family as equal. Dreamers and young vets told their stories and implored their peers to step up and engage.

The Republicans don’t need angry white men, but they squandered their opportunity anyway with Clint Eastwood’s performance last week. The Democrats knew they needed to gin back up the enthusiasm that drove the youth vote in 2008, and the star power out tonight took their responsibility seriously and delivered a sober message. And Eva did it without the chair.