Shortly after Sen. John Thune went straight to the top Tuesday for answers on allegations that Facebook is excluding stories on conservative political topics from its featured spots, the social media outlet agreed to come to Capitol Hill to brief the House Energy and Commerce Committee.

It’s unclear whether Facebook’s decision was related to the letter Thune wrote to Facebook CEO Mark Zuckerberg, asking how the social media site controls its trending topics section.  

In his letter, Thune pointed to media reports that claimed “employees of Facebook routinely suppressed conservative political viewpoints on the social network.” The articles
cited  in the letter said employees were instructed to replace “trending” stories from conservative news sites with ones from mainstream media when possible.  

As chairman of the Commerce, Science and Transportation committee, Thune asked Zuckerberg to respond to a series of questions including how stories in “trending topics” get approved, whether news curators can manipulate the list’s content, and what steps Facebook is taking to investigate these claims.  

Thune also questioned Facebook’s guidelines for its review team and asked if there was a record of curators’ decisions to inject or remove a “trending” story.  

The letter gave Zuckerberg until May 24 to respond and asked to “arrange for your staff, including employees responsible for ‘trending topics,’ to brief Committee staff on this issue.”  

The committee’s ranking member, Democratic Sen. Bill Nelson of Florida was copied on the letter.  

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