'From the river to the sea:' What to know about the pro-Palestine slogan that's roiling American politics right now

"From the river to the sea, Palestine will be free."

At pro-Palestine protests and in activist spaces, it's a rather common refrain, referring to the entirety of the land from the Jordan River and the Mediterranean Sea — land that includes Israel, the occupied West Bank, and Gaza. 

But some Israelis and Jewish people argue that the phrase has a far more sinister meaning — and Rep. Rashida Tlaib's defense of the term is generating significant controversy for the Michigan Democrat within her own party.

Here's what you should know...