Positive ads are having a bit of a renaissance in politics these days. And here's one of the best we've seen.

[posttv url="http://www.washingtonpost.com/posttv/national/campaign-2014-monica-wehby-trust/2014/04/24/4e729ff2-cbec-11e3-b81a-6fff56bc591e_video.html" ]

It's an ad for Monica Wehby, a doctor running for the Republican nomination for U.S. Senate in Oregon produced by FP1 Strategies. And man is it good.

Why? Because it:

a) Shows rather than tells how Wehby's background -- she's the head of pediatric neurosurgery at  Randall Children's Hospital in Portland -- is decidedly different than most people running for office.

b) Conveys a story -- of a newborn with spinal problems -- that sticks with you.

c) Looks different. The image of Lexi Liebelt, the mom, crying as she recounts the story of how Wehby reassured her that her daughter would be ok is powerful. The shots of the now 12-year old Gabby Liebelt are equally moving.

All of that's not to say that Wehby is a sure thing to win her May 20 primary against conservative state Rep. Jason Conger.  She's not. But, seeing an ad like this shows why so many national Republicans believe that if Wehby is the GOP nominee against Sen. Jeff Merkley, the Oregon race could be surprisingly competitive.

Chris Cillizza writes “The Fix,” a politics blog for the Washington Post. He also covers the White House.