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It goes without saying that President Donald Trump's highly controversial tactic of separating migrant families is complicated on the ground.
Attorney General Jeff Sessions announced in early May that the US would refer "100 percent of illegal Southwest Border crossings to the Department of Justice for prosecution," adding "If you are smuggling a child, then we will prosecute you and that child will be separated from you as required by law."
In order to understand how Trump's zero-tolerance policy plays out on the ground, we explain below how and when children are separated from their families, where they go afterwards and how they may get reunited.
Let's start from the beginning: