Brexit section of Tusk letter to EU leaders ahead of Salzburg meeting: "we should reconfirm the need for a legally operational backstop on Ireland" 
While the EU has been working to dedramatise the backstop, its main principle - a legally operational backstop that can be used if and until there is no other solution - remains intact, and is very unlikely to change
Over the past 7 months, the UK has basically not engaged on the backstop. Theories as to why, are most welcome. Let the EU do all the work, and accept the backstop on transfer deadline day? Hope the 27 blink? Last minute UK proposal? Something else?
There’ll be some link between withdrawal agreement & political declaration, but the two are legally distinct, and doesn’t get round substance of backstop. There is some flexibility in political declaration, but it’ll need to be precise enough to not create surprises down the line
For the increasingly likely proposal of a Nov. summit as the place to finalise details of a deal, there will need to be important progress by Oct. EUCO. The idea that 27 will debate details of Gorgonzola and Cornish pasties among themselves is for the birds
Finally, your usual reminder: no backstop, no withdrawal agreement. No withdrawal agreement, no transition. The alternative is no-deal.
