BeaverFever BeaverFever:
This is not the Cold War and incursions, even repeated ones don't necessitate a shoot down. Especially given that this incursion occurred while fighting a common enemy. It just wasn't necessary and is going to fracture an unsteady alliance.
And to further Bart's point - there is no 'common' enemy. There also is no alliance.
There are numerous factions fighting in Syria. There are Assad's forces, who without their brutal ways would be flayed alive if not for support from Russia. There are those opposed to Assad, commonly referred to as 'rebels' or 'opposition'. There are Kurds, who hate Assad and Turkey equally. There is Al Queda in Syria, funded by Qatar, who hate ISIS and Assad and the Kurds. And there are all sorts of variations on all of these themes.
Russia bombs 'ISIS', but make no distinction between Kurds, Turks, Al Queda or Rebels. There are only Assad's forces, The US Coalition, and ISIS.
The US and Allies are supporting the Rebels, and Kurds, minus Al Queda. Saudi Arabia has it's hands in there, sending arms and ammo to different groups. Then there are the soft rebels who will drop their US supplied weapons for ISIS to use. Then there is Hezbolla who fight Assad and ISIS on the Lebanese border . . .
In short, it's one messed up situation. And having Russia playing cold war games doesn't help things in the slightest. But much of the blame for that can be laid at Obama's 'Red Line' and lack of backbone enforcing it.