Seehofer and his party spent hours finding a response to a hard-fought agreement to reduce migration into the European Union and so-called "secondary migration" between member states hammered out by Merkel at a leaders' summit last week.
Sources said Seehofer complained in Sunday's closed meeting with party bosses that he had endured a "conversation with no effect" with the chancellor on Saturday about whether the EU-wide deal and string of bilateral agreements she struck met his demands.
It was not immediately clear whether the CSU would seek to remain in coalition with the CDU and offer a replacement for Seehofer. Alternatively, it could break up the two parties' decades-long alliance, effectively depriving Merkel of her majority in parliament and pitching Germany into uncharted political waters.
Previously, Seehofer threatened to block migrants coming into Germany. That was his right as interior minister, but it was also Merkel's right to fire him if he did.
Seehofer gave Merkel until July 1 to fix the problem.
I commented "Perhaps this buys Merkel time. I am not convinced."
Today we learn that agreement did not satisfy Seehofer, but we have yet to hear from either Seehofer or the CSU.
Some reports say the party has not accepted his resignation.
This Tweet seems to fit best.
The migration dispute was not political "theater" as one German reader suggested.
Mike "Mish" Shedlock