What are the challenges for Bernie Sanders in his presidential bid?

U.S. Senator Bernie Sanders of Vermont speaking at a town meeting at the Phoenix Convention Center in Phoenix, Arizona. Photo credit: Gage Skidmore/CC 2.0, via Flickr

Vermont Senator Bernie Sanders announced this morning he’s running for president in 2020. He almost won the democratic nomination in 2016. Can he do it in 2020? We look how Sanders stacks up against an already crowded Democratic field.