Actor Ben Affleck is coming to the Senate — not the House. (Jason Merritt/Getty Images)

Celebrities testifying on Capitol Hill are a staple. As with most transactions in Congress, there’s something to be gained by both sides: Lawmakers attract attention they typically wouldn’t for their issues, and the VIPs — from Bono to Elmo — get to soak up some of that special gravitas that only a congressional microphone can provide.

Next week, we’ll see a few. Ben Affleck will be speaking to the Senate Foreign Relations Committee about Congo on Wednesday, while actor Seth Rogen is slated to address another Senate panel about Alzheimer’s disease. But a House committee apparently didn’t think Affleck was enough of an expert on the African nation to merit a spot at a similar hearing on the other side of the Dome, Foreign Policy magazine is reporting.

“The meeting would be inappropriate given the wide offering of other experts available to speak on the issue,” FP quotes a Republican aide as saying about the “Argo” actor. Such an appearance was “floated” and rejected.

Ouch — that’s harsh.

And surprising. After all, Affleck has way more serious chops than many a bold-facer we’ve seen on the Hill. It could be that the GOP just doesn’t like Affleck’s Democratic leanings. But the House panel’s snub seems to miss the point about the role celebs play in Washington (hint: it’s not their brains we’re after).

“They buy you a little time,” says Susan Levin, director of nutrition education for the nonprofit Physicians Committee for Responsible Medicine. Her organization relies on big names, enlisting the likes of actress Scarlett Johansson to write letters about school lunches and fitness guru Jillian Michaels to advocate on the farm bill. “They can help you communicate about issues that might at first seem unapproachable or maybe even too complicated to understand easily.”

Famous folk “have the unique ability to raise the visibility and increase awareness,” says Steven Ross, the executive director of the Artists and Athletes Alliance who often squires Hollywood types around town. But he says they can’t just be pretty faces — they have to have at least some credibility. Their lobbying works best on “issues and causes they are educated on and passionate about.”

We’re hoping the Affleck shutout isn’t a hint of a new standard at work — if so, we might never see another celebrity on Capitol Hill again. And wouldn’t it be sad to miss the likes of these?