In an ongoing series congressional correspondent Kelsey Snell looks under the hood at campaigns. From how they raise money to what they do once they have it.This episode, Kelsey looks at political advertising. She talks with two of the most respected political ad makers in the business. One argues that the best ad is the one that goes viral; the other believes the best ad is the one with the clearest message. This episode: campaign correspondent Asma Khalid and congressional correspondent Kelsey SnellConnect:Subscribe to the NPR Politics Podcast here.Email the show at nprpolitics@npr.org.Join the NPR Politics Podcast Facebook Group.Listen to our playlist The NPR Politics Daily Workout.Subscribe to the NPR Politics Newsletter.Find and support your local public radio station.