That Turkey says no to a Swedish NATO application is, according to them, partly due to the fact that Sweden supports the Kurdish guerrilla PKK, and the Syrian armed Kurds, YPG.
Accusations that Sweden denies.
The political goals of the two groups are similar - Kurdish autonomy to some extent, but in different countries.
The Kurds' lack of self-determination is "a regional problem", says Svante Cornell, co-founder of the think tank Institute for Security and Development Policy.
- We have seen that Turkey, Syria, Iraq, Iran, and other external powers such as Russia and the United States, on various occasions have given support to Kurdish groups abroad while trying to counter Kurdish aspirations at home.
So this is a story that has been going on for many years, and that is likely to continue, says Svante Cornell.