Facebook Inc., Twitter Inc. and Google, already under fire for wielding outsized influence on political discourse around the world, are on the brink of another high-stakes decision — whether to give the Taliban a social-media megaphone. 

Their actions will have lasting impacts on the diplomatic stage and on the lives of everyday people in Afghanistan.

The militant group’s rise to power is forcing Silicon Valley’s biggest internet companies to revisit their policies on how to treat controversial political actors. While the Taliban is banned from holding accounts or spreading propaganda on most big online networks, its takeover of the government means the tech giants will soon have to decide whether to expand its access or grant it the ability to manage Afghanistan’s official state social media channels.