A few more

Dear Prime Minister,

The fifth group of refugees have been flown from offshore detention to the USA. President Obama offered to swap 1250 refugees with refugees waiting to get into the US. But since that time, only 139 refugees have left Nauru and 85 from Manus Island.

What about the remaining 1800+? Why is it taking so long? Why have no Iranians, Somalis or Sudanese gone to the US?