Ever since Russian agents and other opportunists abused its platform in an attempt to manipulate the 2016 U.S. presidential election, Facebook has insisted — repeatedly — that it’s learned its lesson and is no longer a conduit for misinformation, voter suppression and election disruption.

But it has been a long and halting journey for the social network.

Although Facebook has spent billions of dollars to avoid a repeat, even CEO Mark Zuckerberg acknowledges the possibility of outcomes unimaginable in 2016, including possible civil unrest and a disputed election.

Is Facebook ready? Experts and even some of its own employees have their doubts.