Policy makers? If the US had those, they wouldn’t have flushed years of sacrifice and treasure in Iraq down the toilet in only a few weeks.
If anything was flushed it was done after 2009. That’s when the Sunni terrorist groups were defeated in Iraq and the Anbar Awakening council disavowed terrorism and sided with the Iraqi government. But Maliki failed to include them in the government. After 2011 there was no longer a US presence or any agreements which could have been used to influence Maliki to be more inclusive. O surrendered the peace to sectarian tribalism.
The 2012 (Dem supported Muslim Brotherhood) Arab Spring destabilized the region including Syria, next door. This, in combination with the Shia shutting out the Sunnis in Iraq’s government brought the re-emergence of Sunni radicalism. First in Syria now in Iraq.