The video uploaded to Kentucky Sen. Mitch McConnell's YouTube channel on March 11 is no ordinary campaign ad:
Sen. Al Franken, a Democrat from Minnesota, invites users to download similar videos from his campaign website. The file includes videos like "Franken reading to children," and "Franken walking with college students."
Candidates in North Carolina, Iowa and Alaska have put up similar footage, too.
"They're putting it out there because they can, because it's legal, because it's what all their competitors are going to be doing, and it's valuable," says Sheila Krumholz, executive director of the watchdog group Center for Responsive Politics.
She tells NPR's Kelly McEvers that the move can be traced back to the Supreme Court's Citizens United decision in 2010. That ruling encouraged the growth of political groups like superPACs, which can raise and spend unlimited amount for or against candidates.
There's a catch: Outside groups and candidates often have very close ties, but they cannot legally coordinate with one another on messaging.
So campaigns can put out b-roll on their own sites, but they can't collaborate with superPACs on what the content should be or how it should be used, Krumholz says.