Immersion versus Bilingual

Which is the better way to teach little kids, newly arrived from Spanish-speaking nations? As usual with K-12 issues, many teachers (practical) just want what works -- but politics (in this case, politics surrounding immigration and American identity) makes "what works" murky.

But this experiment from Johns Hopkins is useful research: Each method, when combined with the same scripted (and good) curriculum called Success For All, works about the same.