Totally disagree with Tulsi on this. The way to end the Takfiri insurgencies is to stop backing regimes that are fostering them like Saudi Arabia, Turkey, Bahrain, Qatar, UAE, etc, and to stop opposing or weakening regimes and/or non-state actors that are opposing them like Iran, Syria, Hezbollah, Iraqi Shia, Taliban, etc. The US also needs to stop facilitating Israeli expansionism. Other than that, Islamism can be contained the same way Communism was contained and eventually fell apart under its own weight. The only serious defensive interests the US has include preventing long-range missile attacks and domestic terrorism sponsored by foreign entities, both of which are made much more likely by US foreign policy. The US is bordered by weak nations on the north and south, huge oceans to the east and west, with no other major powers in the hemisphere, unprecedented levels of wealth and technology, the world’s most expensive military, and no other nations with which trade is important other than nations in the “second zone” of the empire like Canada, Mexico, South Korea, Japan, and England. There is zero reason for the US to be interfering in the internal politics of Asian, African, Middle Eastern, or Latin American nations.
