Should crossing the border without permission be a criminal offense? This had not been a major part of the political discussion until last week, when Democratic presidential hopeful Julin Castro thrust his proposal to decriminalize border crossings before a national audience during the Democratic presidential primary debates.

What was once the province of legal groups and the progressive wing of the immigrant rights movement is now rapidly becoming a consensus position among Democrats hoping to challenge President Donald Trump who used the law to systematically split up migrant families at the border in a widely deplored seven-week experiment last year.

Because debate over the criminalization of border crossings marks new and unfamiliar terrain for most Democratic politicians, misinformation and hot takes abound. To separate fact from fiction, heres a guide to everything you need to know about Castros proposal to decriminalize border-crossing violations.