The key to an alternative seems to either be entryism into CDU by AfD voters or the CSU actually noticing they’re no longer a ‘sister’ to CDU and going their own way.
There’s a hope this year that Merkel is going to lose her seat as she’s pulled a Theresa May and gambled that she can take her seat which has a 50/50 chance of being lost to AfD, rather than parachuting to a safe CDU seat. So we may wake up a month from now with a retired Merkel, laughing at her choice and rejoicing at a broken establishment with no clear plan.
It’s the worst fear in German culture: a lack of order. There’s no one to replace her when she goes.
[spoiler]“entryism into CDU by AfD voters”
Like UKIP in the UK, the party is composed of political refugees from the left and the right. Disillusioned right-wing voters who feel the party has veered too far to the liberal left, and white working class voters from the left who feel their own red/labour/socdem party is no longer there for the hard-working native.
The Conservatives in the UK during the polling period managed to absorb white working class voters from UKIP, something completely unimaginable without the UKIP factor coming into play. They obviously lost them a bit, but nevertheless they had Red Kippers for quite a while and still retain a large element of them.
CDU would pull a huge success if someone from within could encourage entryism and get former SDP voters who are now in AfD to come and invade the party and lead them to victory.
Also, fuck spoilers.