... The backstop is a useful tool to talk about (if it wasn't that there would be something else) in order to (a) ensure nothing gets signed with the EU and (b) force Parliament to block a no deal outcome through a vote of confidence or hijacking another piece of legislation. Then call an election claiming to be the true party looking to deliver Brexit - only prevented by the nasty EU and HoC - taking the wind out of the Brexit Party to a large extent...
That's exactly my thinking. Boris is giving every indication he's not interested in any negotiations with the EU, he's playing to the home crowd, the electioneering has commenced. The self preservation of the Tory party is at the heart of all this grandstanding. They need to kill off the Brexit party (as they successfully did with UKIP). Once done, they'll be in a position to get a deal over the line.
Interesting times ahead!